OPINION OF THE COURT
Smith, J.We hold that, on the facts of this case, a hospital and an emergency room doctor did not owe an intoxicated patient a duty to prevent him from leaving the hospital.
*484I
Plaintiff was brought by a friend to the emergency room of defendant St. Francis Hospital and Health Centers, seeking admission to St. Francis’s detoxification facility, known as “Turning Point.” This was at least plaintiff’s second visit to St. Francis; he had been admitted there in the previous month with suicidal thoughts and had been placed on a “one-to-one watch.” On that occasion, he improved after receiving medication and was discharged. Apparently, no one at the hospital consulted the record of plaintiff’s previous visit when he returned.
There is no evidence that plaintiff was suicidal on his later visit to St. Francis. But he showed signs of severe intoxication, including red eyes, garbled speech and a strong smell of alcohol. His blood-alcohol content was extremely high: .369%. He was, however, alert and able to walk. He was seen by an emergency room doctor, defendant Chandra Chintapalli, and was accepted to the Turning Point program.
About four hours after his arrival, plaintiff was waiting to be transported to Turning Point when he removed an IV from his arm and told a nurse he planned to go home in a taxi. She urged him to call a friend to pick him up, and he agreed. The nurse went to tell Dr. Chintapalli that plaintiff wanted to leave; when she returned, plaintiff was gone. The nurse asked Dr. Chintapalli if she should call the police. The doctor said no, but notified hospital security. Plaintiff left unescorted, and was hit by a car an hour or two later.
Plaintiff sued the hospital, Dr. Chintapalli and the doctor’s professional corporation (defendants in this opinion) for negligence and medical malpractice. Supreme Court denied defendants’ motions for summary judgment. The Appellate Division reversed and granted the motions, holding that defendants had shown prima facie “that they lacked authority to confine the plaintiff upon his departure from St. Francis” and that plaintiff had failed to contradict that showing (Kowalski v St. Francis Hosp. & Health Ctrs., 95 AD3d 834, 835 [2d Dept 2012]). We granted leave to appeal (19 NY3d 809 [2012]) and now affirm.
II
The gist of plaintiffs claim is that defendants should have prevented him from leaving the emergency room. We agree with *485the Appellate Division that defendants had no right, and therefore could have had no duty, to do so.
There are surely few principles more basic than that the members of a free society may, with limited exceptions, come and go as they please. Of course there are people so mentally impaired that they must be denied this right, but that category is a narrow one and does not include everyone who would be safer in a detoxification facility than on the street. Thus the common law permitted the restraint of people whose mental state might make them a danger to themselves or others only in extreme circumstances. As Judge Fuld explained in Warner v State of New York (297 NY 395, 401 [1948]):
“The common law recognized the power to restrain, summarily and without court process, an insane person who was dangerous at the moment. The power was to be exercised, however, only when necessary to prevent the party from doing some immediate injury either to himself or others and only when the urgency of the case demands immediate intervention. On the other hand, insane persons who were not dangerous were not liable to be thus arrested or restrained . . . Emmerich v. Thorley [(35 App Div 452 [1st Dept 1898])] ... is a striking illustration of the sort of case wherein summary restraint is justifiable. There, the plaintiff who had been summarily and forcibly restrained was actually in the act of throwing herself out of a window to escape fancied pursuers” (internal quotation marks and citations omitted).
Today, Mental Hygiene Law § 22.09 specifically addresses the question of when a hospital may retain “a person whose mental or physical functioning is substantially impaired as a result of the presence of alcohol... in his or her body” (Mental Hygiene Law § 22.09 [a] [1]). The statute deals separately with the case of an intoxicated person “who comes voluntarily or is brought without his or her objection” to a hospital or other treatment facility (§ 22.09 [d]) and one “who is brought with his or her objection” (§ 22.09 [e]). In the latter case, the person “may be retained for emergency treatment” if he or she is examined by a doctor and found to be incapacitated to such a degree that “there is a likelihood to result in harm to the person or others” (§ 22.09 [e]); a “likelihood to result in harm” to oneself must be “manifested by threats of or attempts at suicide or serious *486bodily harm or other conduct” that demonstrates a danger of self-injury (Mental Hygiene Law § 22.09 [a] [3]). For the former category—people who, like plaintiff, come to the hospital voluntarily—the Mental Hygiene Law makes no provision for involuntary retention.
Plaintiff concedes that he could not have been retained under Mental Hygiene Law § 22.09. He argues that the Mental Hygiene Law is not the only possible source of a right to confine an intoxicated person. We need not decide that question: Plaintiff cites no other statute, and there is no principle of common law, that would permit the restraint of a patient on the facts of this case. Plaintiff argues that a duty to restrain him flowed from the hospital’s and the doctor’s common-law duty of care, but there can be no duty to do that which the law forbids. To restrain plaintiff on these facts would have exposed defendants to liability for false imprisonment.
Plaintiff points to two specific features of this case which show, he says, that defendants were at fault: the failure to consult the record of plaintiffs previous hospitalization, when he was contemplating suicide, and Dr. Chintapalli’s rejection of a nurse’s suggestion to call the police. Neither fact changes the result. A patient cannot be confined simply because he was having suicidal thoughts a month ago. And the doctor had no duty to call the police; the police could not, on the facts known to Dr. Chintapalli when plaintiff left the hospital, have forced plaintiff to return.
The dissent advances two theories. First, it says that the Mental Hygiene Law is not “implicated” here (dissenting op at 487)—but Mental Hygiene Law § 22.09 (c), (d) and (e) apply on their face to a “general hospital.” Secondly, the dissent argues, not that defendants could or should have prevented plaintiff from leaving the hospital, but that defendants failed “to follow their own protocols” in other ways (dissenting op at 487). Nothing in this record, however, supports an inference that there was any causal connection between any of the alleged departures from protocol that the dissent relies on and plaintiffs injury. This case is about whether defendants had a duty to prevent plaintiff from leaving the hospital, and nothing else.
Accordingly, the order of the Appellate Division should be affirmed, with costs.