Recreational substance users are at risk for seizures by indirect mechanisms, including cerebral trauma, central nervous system infection, ischemic and hemorrhagic stroke, and metabolic derangements such as hypoglycemia, hypocalcemia, and renal failure. Drugs and ethanol can also cause seizures more directly, either as a feature of intoxication (eg, psychostimulants) or of withdrawal (eg, sedatives, including ethanol). In any patient with a seizure, clinicians should consider illicit drug or ethanol use. Seizures in known alcoholics or illicit drug users require workup to exclude treatable coexisting conditions.