The effectiveness of a variety of clinical anticonvulsant drugs was evaluated in the quaking mutant mouse model of epilepsy. In this model, tonic-clonic seizures are easily elicited by handling and the effects of administration of carbamazepine (CBZ), phenytoin (DPH), phenobarbital (PB), diazepam, valproic acid (VPA) and ethosuximide were quantitatively evaluated. Chronic oral administration of CBZ, DPH and PB reduced the frequency of seizures and this was positively correlated with plasma levels of the drugs. The plasma levels of the 10,11-epoxide metabolite of CBZ were found to be approximately 3-5 times that of the parent compound with chronic oral administration. Acute intraperitoneal administration of the other drugs revealed VPA to be an effective anticonvulsant agent, whereas ethosuximide and diazepam were ineffective at dosage levels that are normally effective in mice as determined by classical testing methods such as electroshock and chemoshock. The results of the present study suggest that the quaking mouse may be a simple, reliable and inexpensive animal model for the evaluation of agents effective against focal motor seizures in humans.