Mephenesin acts on internuncial neurons, producing muscle relaxation without hypnotic effects. 30 neurotic patients with anxiety-tension symptoms received 1-2 g. 1-4 times daily as an adjunct to brief psychotherapy. There was relief of symptoms in 26 without production of drowsiness; in all these there was direct awareness of increased muscle tension. In 4, all without appreciation of increased muscle tension, no benefit was obtained.