Denzimol is a new imidazole derivative with anticonvulsant properties. Denzimol suppressed electrically and chemically induced tonic seizures but did not prevent the clonic ones. Denzimol prolongs pentobarbitone sleeping times indicating that drug binds to rat liver microsomes and are potent inhibitors in the rat of mixed function monooxygense activities both in‐vitro and in‐vivo. The antiepileptic activity of the denzimol has been evaluated in patients with poorly controlled partial epilepsy by adding on the drug to the current therapy. Although denzimol increased blood concentrations of carbamazepine, correlation analysis indicated that the improvement was more likely due to intrinsic properties of denzimol. No severe side effects were reported, although several patients experienced nausea and vomiting, which caused 2 patients to drop out. The drug did not show any mutagenic activity when compared with mutagenic standards.