Eggshell Plaintiff Rule

Eggshell Plaintiff Rule

The eggshell plaintiff rule, also called the eggshell skull rule or thin-skull rule, is a principle of tort law under which a defendant who is legally responsible for injuring another person generally must take the plaintiff as the defendant finds them.

In simple terms:

You take your victim as you find them.

A defendant cannot ordinarily avoid liability merely because the plaintiff had an unusually fragile physical or psychological condition that caused the defendant’s conduct to produce a much more serious injury than would have occurred to an average person.

Imagine that a defendant negligently bumps into a person.

The defendant expects, at most, a minor injury.

But the plaintiff has an unusually thin skull. The seemingly minor impact causes a severe brain injury.

The defendant may still be responsible for the plaintiff’s full legally compensable injury.

The defendant does not get to argue:

“I should only be responsible for the injury an ordinary person would have suffered.”

The law generally looks at the plaintiff who was actually injured.

The eggshell plaintiff rule is therefore closely connected to causation, foreseeability, damages, and fairness. It establishes an important boundary between two questions:

1. Was the defendant responsible for causing the injury?
2. How serious was the injury that actually resulted?

The plaintiff’s unusual vulnerability generally does not excuse the defendant from responsibility merely because the extent of the resulting injury was unforeseeable.

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1. The Basic Principle

The central principle of the eggshell plaintiff rule is straightforward:

A defendant is generally liable for the actual consequences of a tortious act even when the plaintiff’s unusual vulnerability makes those consequences unexpectedly severe.

Suppose three people are exposed to the same negligent act.

• Person A suffers a bruise.
• Person B suffers a broken bone.
• Person C suffers a catastrophic injury because of a rare medical condition.

If the defendant’s conduct legally caused the injury, the defendant cannot necessarily argue that liability should be limited to the harm suffered by Person A.

The plaintiff’s unusual susceptibility does not ordinarily reduce the defendant’s responsibility for the actual injury.

This is one of the most important qualifications to the concept of foreseeability in tort law.

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2. Why Is It Called the “Eggshell” Rule?

The name comes from a simple hypothetical.

Imagine that a person’s skull is as fragile as an eggshell.

A defendant negligently strikes the person’s head.

The defendant might reasonably expect only a minor injury.

Instead, the plaintiff suffers catastrophic damage because the skull is unusually fragile.

The rule says that the defendant must generally accept the plaintiff’s vulnerability.

The defendant cannot say:

“I did not know the plaintiff had an eggshell skull.”

That lack of knowledge ordinarily does not eliminate liability for the injury actually caused.

The unusual vulnerability belongs to the plaintiff.

The wrongful conduct belongs to the defendant.

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3. The Rule Is About the Plaintiff’s Condition

The eggshell plaintiff doctrine applies when the plaintiff has an unusual condition or vulnerability.

That vulnerability may be:

• physical;
• medical;
• psychological;
• or, depending on the jurisdiction and circumstances, related to another preexisting condition.

For example, a plaintiff may have:

• brittle bones;
• a preexisting neurological condition;
• an unusually weak blood vessel;
• a latent medical condition;
• a previous injury;
• or an unusual susceptibility to emotional trauma.

The critical question is whether the defendant’s tortious conduct caused the condition to produce a more serious injury than would ordinarily have occurred.

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4. The Defendant Does Not Need to Know About the Vulnerability

A central feature of the rule is that the defendant generally does not need to know about the plaintiff’s unusual vulnerability.

Suppose a defendant negligently causes a minor collision.

The defendant has no reason to know that the plaintiff has a rare medical condition.

The condition makes the plaintiff’s injuries extraordinarily severe.

The defendant may nevertheless be responsible for the resulting harm.

This principle prevents defendants from benefiting simply because the plaintiff happened to be unusually vulnerable.

The law generally does not impose a rule saying:

“If you could not foresee the plaintiff’s vulnerability, you are responsible only for an ordinary injury.”

Instead, the rule is generally:

If your tortious conduct causes the injury, you take the plaintiff as you find them.

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5. Foreseeability and the Eggshell Plaintiff Rule

The relationship between foreseeability and the eggshell plaintiff rule is especially important.

In negligence law, foreseeability often matters when determining:

• duty;
• breach;
• proximate cause;
• and the scope of liability.

But foreseeability does not necessarily require the defendant to predict the precise severity of the plaintiff’s injury.

Consider this example.

A defendant negligently pushes a person.

It is foreseeable that the person might suffer some physical injury.

It may not be foreseeable that the person has an extremely fragile blood vessel and will suffer a life-threatening hemorrhage.

The exact severity may therefore be unforeseeable.

Yet the defendant may still be liable for the full injury if the underlying injury was legally caused by the defendant’s conduct.

This produces an important distinction:

Foreseeability may limit whether conduct creates liability for a type of harm, but the eggshell rule can prevent unforeseeable severity from limiting damages once liability exists.

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6. Unforeseeable Type of Harm vs. Unforeseeable Extent of Harm

This distinction is fundamental.

Suppose a defendant negligently strikes a pedestrian.

Scenario A: Unforeseeable severity

The pedestrian suffers a much more serious injury than an ordinary person would have suffered because of a rare medical condition.

The type of harm—physical injury—is foreseeable.

The extent of the injury is extraordinary.

The eggshell rule may make the defendant responsible for the full injury.

Scenario B: Unforeseeable type of harm

The defendant’s conduct produces a completely different category of harm that falls outside the foreseeable scope of the risk.

That may raise a proximate-cause problem.

Thus:

Unforeseeable severity does not necessarily defeat liability.

But:

An unforeseeable type of harm may affect proximate cause and the scope of liability.

This distinction is essential.

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7. The Eggshell Rule Does Not Eliminate Proximate Cause

The eggshell plaintiff rule does not mean that a defendant becomes responsible for everything that happens to the plaintiff after an accident.

Causation still matters.

Suppose a defendant negligently bumps into a plaintiff.

The plaintiff has an unusual medical condition.

The plaintiff suffers a severe injury.

The defendant may be liable if the negligence legally caused the injury.

But if an entirely independent event later causes another injury, the eggshell rule does not automatically make the defendant responsible for that second injury.

The plaintiff must still establish:

Factual causation + Proximate cause + Legally recognized harm

The eggshell rule modifies the treatment of the plaintiff’s vulnerability. It does not abolish the ordinary requirements of causation.

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8. The Eggshell Rule and Preexisting Conditions

The doctrine frequently appears when a plaintiff already has a medical condition.

Suppose a person already suffers from a spinal disorder.

A defendant negligently causes a minor automobile collision.

The collision aggravates the plaintiff’s condition and results in serious disability.

The defendant may be responsible for the aggravation caused by the tortious conduct.

The defendant cannot necessarily argue:

“The plaintiff was already injured, so I should not be responsible.”

Instead, the law generally asks:

What harm did the defendant’s conduct actually cause?

The defendant is ordinarily responsible for the legally attributable consequences of that conduct, even if the consequences are more severe because of the plaintiff’s preexisting condition.

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9. Aggravation of a Preexisting Condition

The eggshell principle is particularly important when the defendant’s conduct aggravates an existing condition.

Consider:

• Plaintiff has a preexisting back injury.
• Defendant negligently hits plaintiff with a vehicle.
• Plaintiff’s condition becomes substantially worse.
• Plaintiff requires extensive medical treatment.

The defendant may be responsible for the additional harm caused by the collision.

The defendant is not necessarily responsible for every medical problem the plaintiff had before the accident.

The distinction is:

Existing condition ≠ defendant’s responsibility

but

Tortious aggravation of existing condition = potentially compensable harm

The plaintiff generally must establish the portion of the injury attributable to the defendant’s conduct.

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10. The Plaintiff Does Not Have to Be “Normal”

The rule reflects a basic principle of tort law:

The plaintiff does not have to be an average person.

People differ dramatically in:

• physical strength;
• bone density;
• medical history;
• age;
• neurological conditions;
• susceptibility to disease;
• psychological resilience;
• and other characteristics.

Tort law generally does not create a hypothetical “average plaintiff” and then limit the defendant’s responsibility to the injuries that average person would have suffered.

Instead, when a defendant’s wrongful conduct causes actual harm, the law generally evaluates the plaintiff who actually experienced that harm.

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11. The Eggshell Rule and Damages

The doctrine has an especially important effect on damages.

Suppose a defendant negligently causes an accident.

An ordinary plaintiff might suffer:

• $5,000 in medical expenses;
• several weeks of lost wages;
• and a temporary injury.

The actual plaintiff, however, has an unusual condition and suffers:

• extensive medical expenses;
• permanent disability;
• substantial lost income;
• and significant pain and suffering.

If the defendant’s negligence legally caused those losses, the eggshell rule may require the defendant to compensate the plaintiff for the full legally attributable consequences rather than limiting recovery to the amount an ordinary person would have experienced.

Thus, the rule can significantly increase the damages associated with an otherwise relatively minor act.

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12. The Defendant’s Conduct Does Not Have to Be the Sole Cause

As with other negligence cases, the existence of other contributing factors does not necessarily eliminate liability.

A plaintiff may have:

• a preexisting condition;
• another injury;
• a genetic vulnerability;
• or another contributing circumstance.

The relevant question remains whether the defendant’s conduct was a legally sufficient cause of the injury.

For example:

Preexisting vulnerability + defendant’s negligence = aggravated injury.

The defendant may be responsible for the legally attributable aggravation.

This is different from saying that the defendant caused the plaintiff’s original condition.

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13. The “Take Your Plaintiff as You Find Them” Principle

The phrase “take your plaintiff as you find them” summarizes the doctrine.

It means that once the defendant’s conduct gives rise to legal responsibility for the injury, the defendant generally cannot reduce that responsibility merely because the plaintiff was unusually susceptible.

The principle can be expressed in three steps:

Step 1

The defendant commits a tort.

Step 2

The tortious conduct causes an injury.

Step 3

The plaintiff’s unusual vulnerability makes that injury more serious.

The defendant may still be responsible for the full resulting injury.

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14. A Classic Hypothetical

Imagine a defendant negligently throws a small object across a room.

The object strikes the plaintiff.

Ordinarily, such an impact would cause nothing more than a minor bruise.

Unknown to the defendant, however, the plaintiff has a rare medical condition that makes the plaintiff extremely susceptible to internal bleeding.

The plaintiff suffers severe internal injuries.

The defendant argues:

“No reasonable person could have predicted that such a small object would cause such serious harm.”

The eggshell plaintiff rule provides the response:

The defendant may not avoid responsibility merely because the plaintiff’s vulnerability made the consequences unusually severe.

The law does not require the defendant to have predicted the plaintiff’s precise medical condition.

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15. A More Difficult Example

Suppose a defendant negligently hits a pedestrian.

The pedestrian has a serious preexisting heart condition.

The accident causes extreme stress and physical trauma.

The plaintiff suffers a heart attack.

The defendant argues that a heart attack was unforeseeable.

The analysis requires care.

The plaintiff does not necessarily have to show that the defendant should have predicted the exact medical consequence.

Instead, the question may be whether the defendant’s conduct caused a legally recognizable injury and whether the injury falls within the applicable scope of liability.

If the plaintiff’s unusual vulnerability transformed a foreseeable physical impact into a much more serious medical consequence, the eggshell principle may apply.

But courts must still distinguish genuine eggshell cases from injuries that are too remote to satisfy proximate-cause requirements.

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16. Psychological Vulnerability

The eggshell principle is not necessarily limited to bones and physical conditions.

Tort law may also confront plaintiffs who have unusual psychological vulnerabilities.

For example, a defendant’s wrongful conduct might cause severe emotional distress in a person who has a preexisting psychological condition.

The plaintiff’s vulnerability may increase the severity of the resulting injury.

Whether and how the eggshell rule applies to purely emotional injuries varies by jurisdiction and by the particular tort involved.

This is especially important because intentional infliction of emotional distress, negligent infliction of emotional distress, and other emotional-harm doctrines have their own requirements.

The general principle remains relevant, but it should not be applied mechanically.

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17. The Eggshell Rule in Intentional Torts

The eggshell principle is not limited exclusively to negligence.

It can also arise in intentional tort cases.

Suppose a defendant intentionally commits a battery.

The defendant intends only to cause a minor physical contact.

The plaintiff has an unusually fragile medical condition, and the contact causes catastrophic injury.

The defendant may be responsible for the consequences of the intentional tort even though the defendant did not anticipate the extent of the resulting harm.

This illustrates an important distinction:

Intent concerns the defendant’s mental state regarding the tortious act.

The eggshell rule concerns the consequences of that act for an unusually vulnerable plaintiff.

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18. The Eggshell Rule and Punitive Damages

The rule primarily concerns responsibility for compensatory damages arising from the plaintiff’s actual injury.

It does not automatically determine whether punitive damages are available.

Punitive damages generally depend on the defendant’s level of misconduct, such as particularly egregious, malicious, or reckless behavior, depending on the jurisdiction.

Therefore:

Severe damages caused by an eggshell plaintiff do not automatically mean punitive damages are appropriate.

The plaintiff’s vulnerability may increase compensatory damages because it increases the actual harm.

It does not necessarily transform ordinary negligence into aggravated misconduct.

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19. The Eggshell Rule and Comparative Negligence

The plaintiff’s own negligence may still matter.

Suppose:

• Defendant negligently causes an accident.
• Plaintiff is unusually vulnerable.
• Plaintiff is also partly responsible for the accident.

The eggshell rule does not necessarily eliminate comparative negligence.

The plaintiff’s vulnerability concerns the extent of harm.

Comparative negligence concerns the plaintiff’s responsibility for the accident.

These are separate questions.

For example:

Question 1: Did the defendant’s negligence cause the injury?

Question 2: How serious was the injury because of the plaintiff’s vulnerability?

Question 3: Did the plaintiff’s own negligent conduct contribute to causing the accident?

The answers to these questions must not be confused.

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20. The Eggshell Rule and Mitigation of Damages

The plaintiff generally has obligations concerning mitigation of damages.

The eggshell rule does not necessarily permit a plaintiff to allow avoidable losses to accumulate.

For example, if reasonable medical treatment could prevent additional injury, the plaintiff may be expected to take reasonable steps to mitigate damages.

The defendant remains responsible for the consequences of the plaintiff’s vulnerability, but ordinary rules concerning avoidable consequences can still apply.

Thus:

Eggshell rule ≠ unlimited recovery

It simply prevents the defendant from using the plaintiff’s unusual susceptibility as a reason to deny responsibility for otherwise legally attributable harm.

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21. The Eggshell Rule and Medical Treatment

Medical treatment after an accident can raise difficult causation questions.

Suppose:

1. Defendant negligently injures plaintiff.
2. Plaintiff requires medical treatment.
3. Plaintiff has an unusual medical condition.
4. Treatment produces complications.
5. Plaintiff suffers additional harm.

The defendant may potentially remain responsible for subsequent complications if they are legally connected to the original injury.

But courts must separately analyze:

• whether treatment was reasonably necessary;
• whether the complications were foreseeable or legally attributable;
• whether medical negligence intervened;
• and whether another event became a superseding cause.

The eggshell rule does not automatically make the defendant responsible for every later medical event.

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22. The Eggshell Rule and Intervening Causes

This is another important distinction.

Suppose the plaintiff’s unusual vulnerability makes the original injury unusually severe.

That is generally an eggshell issue.

But suppose a completely independent later event causes a new injury.

That may instead be an intervening or superseding cause issue.

The two doctrines should not be confused.

Eggshell plaintiff

The plaintiff’s existing vulnerability makes the consequences of the defendant’s conduct unusually severe.

Superseding cause

A later event may be sufficiently independent and unforeseeable to break the causal chain.

Thus:

Vulnerability concerns the plaintiff.

Superseding causation concerns a later event.

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23. The Eggshell Rule and Foreseeability

A useful way to understand the doctrine is to distinguish foreseeability of injury from foreseeability of vulnerability.

Suppose physical injury from a collision is foreseeable.

The plaintiff’s unusual medical condition is not foreseeable.

The resulting injury is extremely severe.

The defendant may still be liable because the law does not necessarily require foreseeability of the plaintiff’s precise vulnerability.

This prevents defendants from arguing:

“Because I could not foresee this person’s condition, I should not be responsible for the consequences.”

The doctrine generally rejects that argument.

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24. The Rule Does Not Make the Defendant an Insurer

It is important not to misunderstand the principle.

The defendant is not an insurer against everything that happens to the plaintiff.

The defendant must first be legally responsible for the underlying injury.

Only then does the eggshell principle become relevant to the extent of harm.

For example:

No underlying tort → no eggshell liability.

Tort + causation + unusually severe consequences → eggshell rule may expand the defendant’s responsibility for damages.

This distinction prevents the doctrine from becoming unlimited.

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25. A Complete Example

Consider the following hypothetical.

A driver negligently strikes a pedestrian at a crosswalk.

The pedestrian has a rare bone disorder that makes the person’s bones unusually fragile.

The collision causes several fractures and permanently worsens the pedestrian’s physical condition.

The driver argues:

“The collision was minor. I could not have predicted these injuries.”

A court applying the eggshell plaintiff rule would generally focus on whether the driver’s negligence caused the plaintiff’s injury.

If the negligence is established and the plaintiff’s vulnerability explains why the injuries were unusually severe, the driver may be responsible for the full legally attributable consequences.

The driver’s lack of knowledge of the rare condition does not necessarily protect the driver.

However, the plaintiff must still prove:

• the driver’s duty;
• breach;
• factual causation;
• proximate cause;
• and damages.

The eggshell rule does not eliminate these requirements.

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26. A Useful Analytical Formula

The doctrine can be remembered through this formula:

Tortious conduct + legally sufficient causation + unusual plaintiff vulnerability = liability for the actual legally attributable harm

The key word is actual.

The law does not necessarily calculate damages by imagining what would have happened to a hypothetical ordinary plaintiff.

Instead, it asks what harm actually resulted from the defendant’s legally wrongful conduct.

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27. Common Mistakes

Mistake 1: The defendant is liable only for foreseeable injuries

Too broad.

Foreseeability remains important, but the eggshell rule prevents unforeseeable severity caused by the plaintiff’s vulnerability from automatically limiting liability.

Mistake 2: The defendant must know about the plaintiff’s condition

Generally false.

The defendant usually does not need to know that the plaintiff is unusually vulnerable.

Mistake 3: The defendant is responsible for everything that happens afterward

False.

Causation and proximate cause remain necessary.

Mistake 4: The eggshell rule applies only to physical injuries

Too narrow.

It can potentially arise in cases involving psychological or other vulnerabilities, although the precise application depends on the tort and jurisdiction.

Mistake 5: A preexisting condition eliminates liability

False.

A defendant may be responsible for aggravating a preexisting condition.

Mistake 6: The eggshell rule creates strict liability

False.

The plaintiff must still establish the underlying tort.

Mistake 7: Comparative negligence disappears

False.

The plaintiff’s own conduct may still affect recovery under applicable comparative or contributory negligence rules.

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28. The Eggshell Rule on a Law School Exam

When a fact pattern mentions a plaintiff’s unusual vulnerability, immediately consider the eggshell plaintiff rule.

A useful examination structure is:

Step 1: Establish the underlying tort

Was the defendant negligent or otherwise legally responsible?

Step 2: Establish causation

Did the defendant’s conduct cause the injury?

Step 3: Identify the unusual vulnerability

Did the plaintiff have a preexisting or unusual condition?

Step 4: Separate type from extent

Was the type of harm foreseeable even though the severity of the harm was not?

Step 5: Apply the eggshell rule

If the defendant’s tortious conduct caused the injury, the defendant may be responsible for the full legally attributable consequences despite the plaintiff’s unusual vulnerability.

Step 6: Check for limits

Analyze:

• proximate cause;
• intervening causes;
• superseding causes;
• comparative negligence;
• mitigation;
• and damages.

A concise exam statement might be:

The eggshell plaintiff rule provides that a defendant generally takes the plaintiff as found and may be liable for the full extent of harm caused by the defendant’s tortious conduct, even when the plaintiff’s preexisting or unusual vulnerability makes the injury more severe than would ordinarily be expected.

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29. The Deeper Principle: Responsibility for Actual Harm

The eggshell plaintiff rule reflects a broader idea about corrective justice.

Tort law is not merely concerned with predicting what usually happens.

It is also concerned with repairing legally wrongful harm.

If a defendant wrongfully causes an injury, the plaintiff’s unusual vulnerability does not necessarily make the defendant’s conduct less wrongful.

Imagine two plaintiffs:

• one suffers a minor injury;
• another suffers catastrophic injury because of a rare vulnerability.

If the defendant’s conduct is equally wrongful and causally responsible in both cases, limiting the second plaintiff’s recovery merely because the plaintiff happened to be unusually fragile could leave a substantial portion of the legally caused harm uncompensated.

The eggshell rule therefore reflects an important principle:

Fortuity in the victim’s condition does not necessarily shift the consequences of a tort from the wrongdoer to the victim.

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30. The Relationship Between Fault and Consequences

The doctrine also demonstrates a recurring feature of tort law.

The defendant’s level of fault and the plaintiff’s level of harm are not always identical.

A relatively minor act can produce catastrophic consequences.

For example:

Minor negligence → severe injury

That does not necessarily mean the defendant’s negligence was minor in legal consequence.

The seriousness of the plaintiff’s actual injury can determine the extent of compensatory liability even when the defendant did not anticipate that severity.

This is one reason tort damages are generally tied to actual legally attributable harm rather than merely to the defendant’s subjective expectations.

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31. Eggshell Plaintiff vs. Foreseeability: The Key Distinction

The most important conceptual distinction can be summarized as follows:

Foreseeability

Asks whether the relevant kind of harm was sufficiently connected to the risk created by the defendant’s conduct.

Eggshell plaintiff rule

Prevents the defendant from limiting liability merely because the plaintiff’s unusual condition made the consequences more severe than expected.

In simplified form:

Foreseeability asks whether the defendant should be responsible for the kind of harm.

The eggshell rule asks the defendant to accept the plaintiff’s actual vulnerability once that responsibility exists.

This is why the two doctrines can coexist without contradiction.

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32. Why the Rule Matters

The eggshell plaintiff rule is one of the clearest examples of the difference between causing harm and predicting harm.

A defendant may not have predicted the exact injury.

But tort law does not necessarily require the defendant to predict the exact injury.

Instead, once the defendant’s wrongful conduct falls within the applicable scope of liability and legally causes injury, the plaintiff’s unusual susceptibility generally does not allow the defendant to escape responsibility for the consequences.

The rule therefore protects a basic principle of tort law:

The victim’s vulnerability is not ordinarily a defense to the wrongdoer’s liability.

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Key Takeaways

• The eggshell plaintiff rule means that a defendant generally takes the plaintiff as the defendant finds them.
• An unusually vulnerable plaintiff does not ordinarily have to accept a reduced recovery merely because the defendant could not foresee the extent of the injury.
• The defendant generally does not need to know about the plaintiff’s unusual vulnerability.
• The rule commonly applies to preexisting physical or medical conditions and their aggravation.
• The rule can potentially apply beyond physical vulnerability, depending on the tort and jurisdiction.
• The doctrine is closely related to foreseeability, but it does not eliminate foreseeability from tort law.
• The key distinction is between the type of harm and the extent or severity of harm.
• The eggshell rule does not eliminate factual causation or proximate cause.
• It does not make the defendant an insurer for everything that happens to the plaintiff.
• Comparative negligence and mitigation principles may still apply.
• The doctrine can arise in both negligence and intentional tort cases.
• The underlying principle is: once legally responsible for the injury, the defendant generally cannot escape responsibility simply because the plaintiff was unusually fragile.

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Frequently Asked Questions

What is the eggshell plaintiff rule?

The eggshell plaintiff rule is a tort doctrine under which a defendant generally takes the plaintiff as found and may be liable for the full extent of an injury caused by the defendant’s tortious conduct, even when the plaintiff’s unusual vulnerability makes the injury unusually severe.

Why is it called the eggshell rule?

It is based on the hypothetical of a person having a skull as fragile as an eggshell. If a defendant’s wrongful conduct injures that person, the defendant generally cannot avoid liability by arguing that an ordinary person’s skull would not have suffered such serious injury.

Does the defendant have to know about the plaintiff’s condition?

Generally, no. The defendant’s lack of knowledge of the plaintiff’s unusual vulnerability ordinarily does not eliminate liability for harm that the defendant’s tortious conduct legally caused.

Does the eggshell rule eliminate foreseeability?

No. Foreseeability remains important, particularly when determining the scope of liability and proximate cause. The eggshell rule principally prevents unforeseeable severity resulting from unusual vulnerability from automatically limiting liability.

Is the defendant liable for every consequence of an injury?

No. The defendant must still be a legally sufficient cause of the injury, and proximate-cause and other limitations on liability continue to apply.

Does the rule apply to preexisting medical conditions?

Yes. One of its most common applications involves a plaintiff whose preexisting condition makes an injury more serious or causes a defendant’s conduct to aggravate an existing condition.

Does the eggshell rule apply to intentional torts?

It can. The principle may apply when an intentional tort, such as battery, produces unexpectedly severe consequences because of the plaintiff’s unusual vulnerability.

Does the rule create strict liability?

No. The plaintiff must still establish the underlying tort and the necessary elements of that claim.

Can the plaintiff’s own negligence reduce recovery?

Potentially. Comparative or contributory negligence rules may still apply depending on the jurisdiction.

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Conclusion

The eggshell plaintiff rule is one of the most important qualifications to ordinary intuitions about foreseeability in tort law.

A defendant generally cannot say:

“I could not have predicted that this particular person would be injured so seriously.”

If the defendant’s conduct was legally wrongful and caused the plaintiff’s injury, the defendant generally takes the plaintiff as found.

The plaintiff’s unusual vulnerability may explain why a relatively ordinary act produced extraordinary consequences. But that vulnerability does not necessarily transfer the resulting loss from the defendant to the innocent victim.

The deeper principle is one of responsibility:

A wrongdoer generally bears the legally attributable consequences of the wrong, even when the victim’s unusual condition makes those consequences unexpectedly severe.

The eggshell plaintiff rule therefore provides an essential counterbalance to foreseeability. Foreseeability helps determine the boundaries of responsibility; the eggshell rule prevents those boundaries from being artificially narrowed simply because the plaintiff was unusually vulnerable.

Further Reading

For an accessible overview of negligence and tort principles, see Cornell Law School’s Legal Information Institute:

Cornell LII — Negligence

For broader background on tort law:

Cornell LII — Tort