Administration of naloxone hydrochloride is the standard treatment for heroin overdose. Naloxone is simple to administer, effective and has a very low risk of harm. Prescribing naloxone to heroin users for later use in case of need is a simple, inexpensive harm-reduction measure that has the potential to reduce mortality from heroin overdose. Some physicians in the USA may be discouraged from distributing naloxone, however, by legal concerns. A legal analysis ﬁnds that the legal risks are low. Prescribing of naloxone in the USA is fully consistent with state and federal laws regulating drug prescribing. The risks of malpractice liability are consistent with those generally associated with providing healthcare, and can be further minimized by following simple guidelines presented.