This report summarizes the results of nine diagnostic radiographic studies done double blind crossover comparing glucagon to placebo and to anticholinergic drugs in volunteers. In seven studies the subjects were administered drug intramuscularly and in two studies intravenously. There were five diagnostic studies of the upper gastrointestinal tract, one for esophageal varices and three of the colon. The results indicate that glucagon can be given intramuscularly and intravenously. When given intravenously it has a rapid onset and predictable length of action depending on the dose given. Reports of side effects were few consisting primarily of nausea and or vomiting. These results indicate that glucagon is the drug of choice for hypotonic diagnostic examinations.