In 1933, when benzedrine (beta-phenylisopropylamine) sulfate was first used in the treatment of narcolepsy,1it was noticed that the patients being treated not only stopped having their attacks but also reported that they tired less easily and felt more energetic in general. It was therefore thought advisable to experiment with benzedrine sulfate in conditions in which asthenia is a prominent symptom. Twenty-eight patients with postencephalitic Parkinson's disease, ten patients with arteriosclerotic Parkinson's disease and twenty-two patients with psychoneurosis have been given benzedrine sulfate for periods varying from four weeks to sixteen months. The oldest patient in the postencephalitic group was 54, the youngest 15, with the average age 32. A history of encephalitis was definite in seventeen patients, was probable in four and could not be obtained in seven. The clinical picture was characteristic in every case, though the following signs varied from patient to patient: rigidity of the