Favored by unusual clinical facilities, I have gradually evolved and established in practice a method of treating gastric and duodenal ulcers. The method is based on well-recognized principles underlying the healing of ulcer. Old and established facts of physiology are largely utilized. The results of treatment are far beyond early expectations. The treatment consists essentially in accurately protecting the ulcer from gastric juice corrosion until healing of the ulcer takes place. After an experience of twelve years in applying the principle involved in the treatment, I am convinced that the vast majority of cases of gastric, and more particularly duodenal, ulcer now treated surgically, and with indications commonly accepted as justifiable, can be readily and more quickly cured by the management advocated. As I understand the ulcer problem, the principles involved in treatment are centered about these important and fundamental questions: What are the causes of peptic ulcer? What retards