The Centers for Disease Control and Prevention this week alerted health care providers to an outbreak of acute hepatitis related to a nutritional supplement used for weight loss and muscle building. All but five of the 29 patients reported using the OxyELITE Pro nutritional supplement within 60 days of illness onset. Eleven patients were hospitalized, one patient died and two received liver transplants. The cases were reported in Hawaii, but CDC is working with state health departments to determine if the outbreak is national in scope. Clinicians evaluating patients with acute hepatitis should ask about consumption of dietary supplements, and report patients meeting the case definition to the local or state health department and Food and Drug Administration’s MedWatch program.