When cimetidine (CIM) is administered together with the anti-epileptic drug carbamazepine (CBZ), a drug interaction may cause a rise in plasma concentrations of CBZ, which can result in CBZ-related toxic symptoms. The aim of this cross-over study was to investigate whether CIM influences the disposition and kinetics of the new anti-epileptic oxcarbazepine (OXC) and its metabolites. In 8 healthy volunteers there was no difference in AUC, Cmax or tmax when OXC was administered either with or without CIM. The results of this study suggest that in the treatment of epilepsy OXC offers an important advantage over the established anti-epileptics, especially when concomitant therapy with CIM is required.