Bipolar disorder is a common recurrent illness with high levels of chronicity. Treatment resistance persists despite the use of established medications, such as lithium and valproate. New medications are required for the treatment of refractory cases. Retrospective and open-label trials have suggested that the anticonvulsant topiramate may be efficacious in bipolar disorder. There is a need to clarify the evidence available in the form of randomised controlled trials for its use in bipolar disorder.