The anxiolytic effects of chlordiazepoxide (CDP) in the Geller-Seifter rat conflict test have been compared with those of muscimol and sodium valproate in order to evaluate the possible role of GABA in the anxiolytic action of the benzodiazepines. The anticonflict activity of CDP was inhibited by the benzodiazepine antagonist Ro15-1788, as well as by bicuculline and picrotoxin. The weaker anticonflict effect of muscimol was overcome by both bicuculline and picrotoxin. Sodium valproate had a marked anticonflict effect which was only inhibited by picrotoxin. Thus, while the anxiolytic action of CDP depends on GABA function in some way, it can be distinguished from the effects of muscimol and sodium valproate which appear to act at the GABA receptor and the chloride ion channel, respectively.