BENZEDRINE (beta-phenylisopropylamine or benzyl methyl carbinamine), one of the sympathomimetic amines structurally related to ephedrine and epinephrine, has recently been the subject of considerable interest. Because of its volatility and of its constrictive action on the nasal mucosa, it has been proved of value in the treatment of rhinological affections (1). Its stimulating effect on the central nervous system has led to its use, as the sulphate, in the treatment of narcolepsy and of certain depressed and fatigue states (2). Myerson and Ritvo (3), furthermore, have claimed that the sulphate, by its effect on smooth muscle, relaxes spasm of the gastro-intestinal tract and so aids in the roentgen diagnosis and in the treatment of certain digestive disturbances. Myerson, Rinkel, and Dameshek (4) have reported that it also markedly increases the acid secretion of the stomach. This investigation was undertaken with the view of studying, by roentgen examination and by intubation of the stomach and duodenum, certain effects of benzedrine sulphate, in safe dosage, on the gastro-intestinal tract, both in normal subjects and in hospital patients. Inasmuch as the results in some respects are in agreement, but in others are at variance, with those of previous workers it is believed that they deserve consideration. Roentgen Studies The effect of benzedrine sulphate upon the gastro-intestinal tract was studied roentgenologically in 28 subjects. These were grouped as follows: Technic.—A barium-and-water mixture consisting of five ounces of barium and five fluid ounces of water was orally administered for the study of the stomach and small intestine and the entire examination was conducted under fluoroscopic control, with interval roentgenograms as indicated. Benzedrine sulphate, usually in a dosage of 20 mg., was given orally in the early part of the study, but later, in order to avoid delay in absorption, by subcutaneous injection. In each of the normal subjects and in some of the patients, a control examination preceded the benzedrine study. All of the patients having duodenal ulcer or duodenal spasm were first studied fluoroscopically without the drug. When, after sufficient time and manipulation, the duodenum could not be filled, 20 mg. of the benzedrine sulphate was given subcutaneously and the fluoroscopic examination continued. In some of the colon cases, the drug was given during the administration of the barium enema, in others it was given after the colon had been filled. Normal Group.—The results in the four subjects of this group were almost identical. Very little effect on gastric peristalsis was noted. The average time for peristalsis to begin after ingestion of the barium was one minute with it. The depth and speed of the peristaltic contractions were not appreciably altered.