Three experiments were performed in order to find if carbamazepine interacts with dopaminergic systems. In the first experiment carbamazepine itself did not induce stereotypy but it potentiated the apomorphine-elicited stereotypy. The potentiation was no longer seen in the second experiment with carbamazepine given chronically. Moreover, stereotyped behaviour was reduced when apomorphine was administered alone after chronic carbamazepine administration. In the third experiment it was shown that carbamazepine together with chronic haloperidol administration or with rapid eye movement-sleep deprivation prevented the development of dopaminergic supersensitivity. These experiments support the hypothesis of a dopaminergic effect of carbamazepine.