Intravenous Mogadon was administred to 12 patients with frequent and/or prolonged seizures, to 6 patients with childhood epileptic encephalopathy with diffuse slow spike-waves, and to 2 with photic induced seizures. Clinically and electroencephalographically 11 of the first 12 patients were improved by the treatment; 3 of the 6 patients with Lennox syndrome were also improved, as well as the two with spontaneous and photic induced clinical and electroencephalographic disorders. Since drowsiness was the most frequent side effect of the drug, only patients with chronic cerebral disorders were used in this study. The clinical and electroencephalographic effects were similar to those of intravenous Valium. Some aspects of the action of this drug in the Lennox syndrome are discussed.