The anticonvulsant effects of gamma vinyl GABA (GVG) were investigated against pentylenetetrazol (PTZ) seizures, while sodium valproate (VP) was used as positive control. At 1000 and 1500 mg kg-1 GVG was found to decrease seizure intensity either in 4 or 24 h, as effectively as VP. At 2000 mg kg-1 GVG was found to be almost ineffective. At both doses and both time spans of drug action, seizure latency was prolonged, compared to controls and VP group.