Twelve asymptomatic subjects cooperated in each of 2 studies. In Study I glucagon was compared to placebo and to atropine sulfate 1 mg. In Study II glucagon 2 mg. was compared to placebo and to propantheline bromide 30 mg. Drugs were given intramuscularly, double-blind, and crossover. When the subjects received glucagon, the radiologist reported that motility and tonicity were decreased and that the drug effect was significantly (p<0.001) greater at 10 and 30 minutes than when placebo was given. Sixty minutes after receiving glucagon the tonicity and motility of the stomach and duodenum differed little from that seen with placebo. Small bowel motility was also significantly (p<0.05) less after glucagon than after placebo. Stomach and small bowel tonicity and motility were significantly (p<0.05) decreased following atropine sulfate and propantheline bromide at 10, 30, and 60 minutes as compared to placebo. Tonicity and motility of the duodenal bulb at 60 minutes and duodenal loop at 30 and 60 minutes were also decreased (p<0.05) following atropine sulfate administration. A similar effect was observed after propantheline bromide was given; the onset of action was somewhat sooner following propantheline bromide than after atropine sulfate. Glucagon was significantly (p<0.05) better than either anticholinergic in the examination of the stomach, duodenal bulb, and duodenal loop. Pulse, blood pressure, and pupil size were obtained at each session and all subjects were questioned concerning side effects. After the administration of propantheline bromide, all subjects reported dryness of the mouth, 5 experienced nausea, 6 reported headaches, and 10 had urinary retention for 4 to 6 hours. After atropine sulfate there were 8 reports of dryness of the mouth and 3 of nausea. When glucagon was given, there was an average of 7.5 reports of nausea and 4.5 reports of vomiting. The results of this study indicate that the decrease in the tonicity and motility of the stomach, duodenum, and small bowel was more predictable and the side effects were fewer with 2 mg. of glucagon than with 1 mg. of atropine sulfate or 30 mg. of propantheline bromide.