The use of herbal remedies and dietary supplements is widespread throughout the world, and use may be increasing. These are taken for a wide range of perceived benefits, such as energy and memory enhancement and treatment of specific conditions. Individuals with and without epilepsy may use these substances and may not inform their treating physician unless specifically asked. Inquiry about herbal medicine and dietary supplement intake should now be part of routine clinical history taking. Anecdotal accounts suggest that some herbal substances may have anticonvulsant effect, but randomised double-blind controlled trails are lacking. Alternatively many herbals and dietary supplements may predispose to seizures in individuals without epilepsy and worsen seizure control in those with epilepsy. In this article, we review the potential anticonvulsant and proconvulsant effects of herbal remedies and dietary supplements and discuss the potential interaction between these herbal substances and conventional anticonvulsant medications.