A 27-year-old man was admitted with tremulousness, diaphoresis, tachypnea (28 breaths/min), full-body rigidity, irritability, paranoia, and auditory and visual hallucinations 2 days after stopping long-term gamma-hydroxybutyrate (GHB) and 8 hours after stopping alcohol intake. He received intravenous fluids and tapering dosages of lorazepam to control agitation and rigidity, and recovered with no significant sequelae after 8 days. Abrupt cessation of GHB after high-dosage abuse can precipitate a clinically significant withdrawal syndrome. Lorazepam should be considered for treatment of GHB withdrawal. Concomitant alcohol abuse may mask early GHB withdrawal symptoms and exacerbate withdrawal.