Status epilepticus (SE) is a state of continuous epileptic activity, the duration of which varies from minutes to hours according to etiology. It may exhibit the various clinical expressions of epileptic seizures: convulsive clonic, tonic, or tonic-clonic, nonconvulsive including focal or absence, the latter being typical or atypical; it may be focal, unilateral, or bilateral. Mixed seizure types may affect epileptic encephalopathies (i.e., Lennox-Gastaut syndrome). SE may consist of a single seizure or repeat seizures without recovery of consciousness. It may be symptomatic of some acute brain damage or complicated epilepsy, either at onset or in the course, usually symptomatic although occasionally idiopathic (i.e., occipital epilepsy). A clue to diagnosis is drawn from clinical characteristics including history but nonconvulsive SE requires EEG recording. Specific conditions need to be identified, namely those occurring after acute nonspecific infection: " hemiconvulsion-hemiplegia-epilepsy" (HHE) syndrome and " fever-induced refractory epileptic encephalopathy in school age children" (FIRES) begin with status epilepticus. Appropriate treatment requires identification of the cause, including some epilepsy syndrome. This permits etiological in addition to symptomatic treatment. Brain energy supply is a crucial component: drugs that may alter cerebral blood flow (e.g., barbiturates) should be restricted to specific conditions. Nonchemical treatment, including the ketogenic diet, may play an increasing role.