Valproic acid, a branched chain carboxylic acid, has a broad spectrum of action as an antiepilepsy drug. While effective in myoclonus syndromes and absence epilepsy, the drug has efficacy for patients with generalized convulsive and partial seizures as well. Mechanisms of action are similar to other drugs used to treat epilepsy, in that valproate limits sustained repetitive firing by actions on the voltage sensitive sodium channel. However, the drug facilitates the removal of glutamate from synaptic regions by up regulating glial glutamate transporters while prolonging the action of GABA by limiting production of inhibitory transmitter transporter proteins. Adverse effects include hepatotoxicity that requires informing patients and establishing clinical monitoring plans. Teratogenicity occurs with valproate and requires informing patients and careful monitoring in women during pregnancy.