Drug-induced disturbances in reproductive hormones and gonadal morphology have been observed both in patients with epilepsy and in non-epileptic animals. Less is known about the influence of newer antiepileptic drugs including lamotrigine on reproduction. Lamotrigine is now increasingly used both in epilepsy and psychiatric disorders. Sixty-five Wistar rats were fed by gastric tube either 5 mg kg(-1) lamotrigine solution (males=15, females=20) or 0 (vehicle control, males=15, females=15) twice daily for 90 days. In males, no significant differences were found in body or testicular weight. Testicular atrophy was observed in one control animal and in two of the rats receiving lamotrigine. No morphological changes were seen in the other organs investigated (liver, kidney, pancreas, brain, lymphatic tissue, heart). None of the animals showed over-expression of p53. No significant differences were observed between the control rats and the male rats receiving lamotrigine regarding testosterone, FSH and LH. In females, no changes in ovarian morphology or alterations in other tissues were observed. Serum testosterone, FSH, LH, insulin and progesterone remained unchanged in the lamotrigine treated animals, while serum estrogen was significantly reduced.