Sodium valproate and clonazepam were given in combination to 17 refractory epileptic patients and their progress was reviewed clinically and by EEG's. Even though plasma concentrations of sodium valproate and conventional anticonvulsants were monitored and adjusted according to individual requirements, combination therapy consisting of valproate and clonazepam was ineffective in controlling seizures in the majority of patients. A further 40 patients receiving clonazepam were reviewed in relation to adverse reactions. 22 patients in this group suffered from undesirable effects attributable to clonazepam. These effects were managed by cessation of the drug or a reduction in the dose. The commonest side effects were drowsiness, loss of concentration, irritability and aggression.