The legal concept of “duty to warn” is not new, but it is one ED providers often misunderstand.1 “It basically covers third parties, somebody who is not warned properly. That duty goes back on the physician,” says Gregory Moore, MD, JD, an attending physician at the Mayo Clinic in Rochester, MN, and at the Maricopa Medical Center in Phoenix.

If EPs are aware of “duty to warn,” it is probably because of the landmark 1976 Tarasoff decision.2 That case involved a patient who threatened to kill a specific person. The psychiatrist contacted the police about the threat, but failed to warn the intended target or her immediate family directly. “Calling the police isn’t necessarily going to be sufficient to protect the EP,” Moore notes.

Also, the patient does not need to name a specific person for the duty to warn to exist. “If the threat is made toward a defined group as opposed to a specific person, you need to warn the group,” Moore explains.

If a patient made similar threats during previous ED visits but never acted on those, that does not mean current statements can be ignored. “Sometimes, the physician’s defense is, ‘He’s been saying it for years,’” Moore reports.

The EP should warn the person who is threatened. If that individual cannot be reached, the EP should document their efforts, and notify law enforcement.

The Tarasoff case was the first to outline the requirement of duty to warn. “That was later amended to ‘duty to protect,’” notes James D. Calvert, PhD, MSCP, LSOTP, a senior lecturer in the department of psychology at Southern Methodist University in Dallas.

If the client of a health professional (which could be an ED patient) threatens to seriously harm or kill someone else, that professional is supposed to try to find that third person, and warn them of the threat. The ED provider may not know who the person is if the patient talks about harming a spouse or co-worker without giving a name. “Tarasoff made it so that you would need to find and contact and warn the third party,” Calvert says.

The law applies only to the state of California. “However, since it was the first and most famous case on duty to warn, it has become the most taught perspective on duty to warn. Some states have adopted that view, some haven’t,” Calvert reports.

The Texas Supreme Court found there is not a duty to warn a third party because of statutes on confidentiality.3 “Indeed, they pointed out that telling a third party is a breach of confidentiality,” Calvert notes.

Those Texas justices ruled that telling police or other professionals may still be a breach of confidentiality, but would need to be assessed in another case brought before them. “However, the general application based on their wording has been that because of the ethical requirement of duty of care, getting help for a potentially dangerous client by contacting another professional to get them more intensive treatment is a reasonable and required standard of care,” Calvert explains.

Contacting police or other emergency personnel would not happen to report clients for a crime. “It would be because those are the professionals in the community authorized to get clients into emergency care, such as a 72-hour hold in a hospital,” Calvert says.

Not all states have adopted a position on duty to warn. Many ED providers are unaware of their state’s requirements. To minimize risks, Calvert says providers should “consult with others when uncertain, do the best care you can for your patient, and document everything you do.”

EPs are unlikely to realize their duty to warn obligations go beyond just threats of violence. Here are two examples:

EPs are obligated to warn patients about the side effects of medication that could result in harm to others. In one case, a patient with a history of migraine headaches received the same medications as in many previous ED visits. No one provided a warning to the patient about side effects. Shortly after leaving the ED, she was in a motor vehicle accident that left her a paraplegic. The patient later sued successfully, winning $1.3 million.4

“You have to tell the patient not to drive on the medication because they might hurt somebody else,” Moore says.

Since the EP cannot warn the general public of the dangers, the duty to warn is discharged when the patient is notified of the risk. This should be documented in discharge instructions.

EPs are obligated to warn if there is a risk of infectious disease. One malpractice case involved a man who died from Rocky Mountain spotted fever after coming to an ED with headaches, fevers, and chills.5 The patient’s wife died shortly after from the same condition.

The son sued the EP successfully for failure to warn his mother she was at risk. The disease is not contagious, but infected ticks cluster geographically. The defendants appealed, but another court upheld the verdict. The court ruled that even though the wife was not in danger of contracting the disease from her husband, the EP still was legally obligated to warn her of the foreseeable risks.

“If somebody has gonorrhea and a third party might get disease from this patient, that you now know has the disease, the physician has a duty to warn that person,” Moore adds.

How can the EP can warn all third parties at risk, since the EP does not know all the people who will come in contact with the patient? “You try to displace the duty to warn onto the patient,” Moore offers.

ED providers must instruct the patient to warn others that he or she has been diagnosed with an infectious disease, whether it is tuberculosis or COVID-19. “It should be in the discharge instructions, that you warned them to notify people who could be affected,” Moore says.


  1. Pfaff R, Berkeley RP, Moore G, Heniff M. Duty to warn in the emergency department: Three medical legal cases that illustrate providers’ broad risk and liability. Clin Pract Cases Emerg Med 2020;4:285-288.
  2. Tarasoff v. Regents of the University of California. 17 Cal. 3d 425, 551 P.2d 334, 131 Cal. Rptr. 14 (1976).
  3. Thapar v. Zezulka. 994 S.W.2d 635 (Texas 1999).
  4. West v. Columbia Med. Center. Texas 5th Circuit Court. No. cv00594 1997. Nov. 4, 2019.
  5. Bradshaw v. Daniel. Supreme Court of Tennessee. June 1, 1993. 854 S.W.2d 865.