LTG, lamotrigine is a new antiepileptic agent chemically unrelated to any established drugs in use. The safety and the efficacy of LTG (564.5 +/- 74.4) mg/day was evaluated as add-on therapy (plus CBZ) in a placebo controlled study of 34 patients with refractory partial complex and/or partial secondary generalized seizures. The incidence of adverse effects of the drug is low and the unwanted effects are reversible. The long half-life and lack of effect on other AEDs will render LTG an easily dosable addiction to a patient's existing regimen. Reduction in the total number seizures was recorded in 61.4% of patients. We conclude that LTG is an effective AED for treatment of therapy-resistant partial seizure.