The emergency physician assessing and treating a patient with a psychiatric emergency will frequently encounter patients with withdrawal syndromes. Clinically, ethanol withdrawal manifests as increased autonomic symptoms, alcohol withdrawal hallucinosis, alcohol withdrawal seizures, and delirium tremens (DTs). Patients with minor symptoms of alcohol withdrawal without a history of DTs and who intend to continue drinking are often discharged without receiving any specific medications. Sedative hypnotic agents such as barbiturates and benzodiazepines, like ethanol, exert their effects by means of augmentation of GABA inhibitory neurotransmission. Therefore, symptoms of withdrawal from these agents are very similar to alcohol withdrawal. Withdrawal from Gamma-hydroxybutyrate and its precursors are similar to alcohol withdrawal and other sedative hypnotics. Opioid withdrawal is not life-threatening. However, it is very unpleasant and painful to endure. Due to cross-reactivity of the different opioids, any opioid can be administered to alleviate withdrawal symptoms.