Purpose: To assess the available evidence for the belief that valerian, highly recommended in the past for treating epilepsy, possessed real anticonvulsant effectiveness.
Methods: Review of available literature.
Results: In 1592, Fabio Colonna, in his botanical classic Phytobasanos, reported that taking powdered valerian root cured his own epilepsy. Subsequent reports of valerian's anticonvulsant effectiveness appeared. By the late 18th and early 19th centuries, it was often regarded as the best available treatment for the disorder. Valerian preparations yield isovaleric acid, a substance analogous to valproic acid and likely to possess anticonvulsant properties, as isovaleramide does. In favorable circumstances, high valerian doses can be calculated to have sometimes provided potentially effective amounts of anticonvulsant substance for epilepsy patients.
Conclusions: Valerian probably did possess the potential for an anticonvulsant effect, but the uncertain chemical composition and content of valerian preparations, and their odor and taste, made it unlikely that they could ever prove satisfactory in widespread use.