Licarbazepine, (R)- is a hydroxy derivative of R-licarbazepine acetate. Eslicarbazepine acetate (ESL), or S-licarbazepine acetate (ESL), Licarbazepine, (R)- acetate and their racemic mixture, as well as other related compounds, were orally assessed in rats for anticonvulsant activity and compared with carbamazepine (CBZ) and oxcarbazepine (OXC). Metabolism of OXC and its derivatives varies considerably between species. Rats metabolize ESL to OXC with minimal (S)-licarbazepine or Licarbazepine, (R)- metabolites. Licarbazepine, (R)- undergoes a further oxidation to the trans-diol metabolite, demonstrating an increased predisposition to earlier inactivation. Administration of ESL and of eslicarbazepine significantly protected mice against Maximal electroshocks-induced seizures, whereas that of Licarbazepine, (R)- failed to provide protection. This finding raises doubts on the contribution of Licarbazepine, (R)- as an active anticonvulsant.