Valproate is an antiepileptic drug with a wide spectrum efficacy in the management of various types of seizures and epileptic syndromes. In addition to its efficacy in epilepsy, valproate has been found to have therapeutic effects in various psychiatric disorders, including manic states, bipolar, panic and schizophreniform disorders and in the prevention and acute treatment of migraine. Valproate is available in various formulations that differ primarily in their absorption profiles. The purpose of this review article is to highlight the most important pharmacokinetic and pharmacodynamic properties of this drug that all clinicians should be aware of when using it as an antiepileptic, antimigraine, or mood-stabilizing agent. We review its use with other common antiepileptics or psychotropic drugs and the pharmacokinetic interactions with commonly used drugs. We also review its tolerance and toxicity profile in the various age-groups and devote a section to the particular problems associated with its use in patients with renal and hepatic failure and in women of gestational age.