Monkeys were treated intravenously with various anticonvulsant drugs before and after the intravenous administration of gamma hydroxybutyrate (GHB). Continuous electroencephalographic (EEG) and temperature monitoring was performed throughout all experiments. The GHB-induced EEG changes were abolished by ethosuximide and clonazepam, marginally improved by diazepam, and unaffected by phenobarbital. The GHB induced myoclonic jerks were abolished by ethosuximide, significantly improved by diazepam, and worsened byclonazepam. Phenobarbital was effective in diminishing the frequency of GHB-induced myoclonic jerks only when given prior to administration of GHB. The GHB-induced stupor was improved only by ethosuximide. The GHB model of petit ma1 seizures is quite specific for drugs used in this disorder. GHB may play a role in the pathogenesis of absence seizures in children.