We studied 57 patients with poorly controlled or atypical seizures to identify hysterical attacks with a provocative test consisting of initiation and termination of an attack with suggestion and saline injection during electroencephalographic (EEG) monitoring. Using this method, we diagnosed 48 patients as having hysterical attacks. Three additional patients had spontaneous hysterical attacks during routine recordings. Of the 51 patients with hysterical attacks, 78% were female. Two-thirds of the patients were between the ages of 20 and 35 years. Thirty-two patients had taken anticonvulsants before the study. Each patient's hysterical attack, aura, and postictum was stereotyped, and the 6 patients subject to both hysterical and organic seizures described the two types of attacks as different stereotyped behaviors. Tongue laceration, urinary incontinence, and postictal confusion were common. Twelve patients had evidence of past or present neurological disease. Abnormal EEGs were recorded in 37% but only 12% had spike or spike and wave discharges. The provocative EEG test employing saline and suggestion is a useful tool in the diagnosis of hysterical "seizures."