BETAZOLE hydrochloride (Histalog), a synthetic analog of histamine, has been employed for the past 6 years as the parenteral stimulant to gastric acid secretion in the standard 2-hour gastric analysis employed by this clinic.1With proper intragastric placement of the tube, doses of 0.1 mg. per kg. of body weight have been equal in potency to the previously employed 0.01 mg. per kg. of histamine diphosphate. The chief advantage has been the almost complete disappearance of headache and flushing, frequent and occasionally troublesome side effects following injection of histamine.Three years ago the oral preparation of betazole hydrochloride was made available and a comparison of the two forms of administration was undertaken. The purpose of this report is to compare the effectiveness of oral and intramuscular betazole hydrochloride as a stimulant to gastric acid secretion.MethodEach subject was studied by the standard 2-hour gastric analysis.2The