Preparations and extracts of valerian, as well as isovaleramide, isovaleric acid, and certain structurally related compounds, exhibit clinically significant pharmacological properties that implicate a treatment for a variety of pathological conditions, including spasticity and convulsions, which are ameliorated by effecting a modulation of CNS activity. The compositions in question generally are non-cytotoxic and do not elicit weakness or sedative activity at doses that are effective for the symptomatic treatment of such pathological conditions.