During August-September 2012, the New York City Department of Health and Mental Hygiene (DOHMH) was notified by the New York City Poison Control Center regarding three patients who experienced serious adverse events after anesthesia-assisted rapid opiate detoxification (AAROD) at a local outpatient clinic. All three patients required hospitalization, and one subsequently died. DOHMH issued an order requiring that the clinic cease performing AAROD pending an investigation and searched for additional cases of AAROD-related serious adverse events at the clinic and elsewhere in New York City for the period September 2011 to September 2012. That search found no serious adverse events at clinics other than the one implicated. Of the 75 patients who underwent AAROD at the implicated clinic during January-September 2012, two died, and five others experienced serious adverse events requiring hospitalization. As a result of the findings, the New York State Department of Health, the New York Office of Alcoholism and Substance Abuse Services, and DOHMH jointly issued a Health Alert informing New York health-care providers of AAROD-associated serious adverse events and recommending that they avoid use of AAROD in favor of evidence-based options for opioid dependence treatment.