The pharmacology of anticonvulsant drugs is reviewed with emphasis placed on the treatment of canine and feline epilepsy. Due to pharmacokinetic reasons, only phenobarbital, primidone, and, with certain limitations, the benzodiazepines can be used in dogs. Bromides may be given additionally in cases that cannot be controlled with phenobarbital or promidone therapy. In cats, diazepam has been shown to be very useful because no tolerance develops to the antiepileptic effect in this species.