Convulsive status epilepticus is an emergency that is associated with high morbidity and mortality. The outcome largely depends on etiology, but prompt and appropriate pharmacological therapy can reduce morbidity and mortality. Etiology varies in children and adults and reflects the distribution of disease in these age groups. Antiepileptic drug administration should be initiated whenever a seizure has lasted 10 minutes. Immediate concerns include supporting respiration, maintaining blood pressure, gaining intravenous access, and identifying and treating the underlying cause. Initial therapeutic and diagnostic measures are conducted simultaneously. The goal of therapy is rapid termination of clinical and electrical seizure activity; the longer a seizure continues, the greater the likelihood of an adverse outcome. Several drug protocols now in use will terminate status epilepticus. Common to all patients is the need for a clear plan, prompt administration of appropriate drugs in adequate doses, and attention to the possibility of apnea, hypoventilation, or other metabolic abnormalities.