The effect upon stomach ulceration of 48 hr. of severe restraint without food and water, and of injections of reserpine, were studied in rats. Ulcers were most numerous in the immobilization-reserpine group, next most numerous in the immobilization-no reserpine group, and practically nonexistent in the nonrestrained groups. Stomach contents were less acid for ulcerated rats, suggesting that ulceration was accompanied by increased gastric motility or decreased secretion, consistent with reports that reserpine increases gastric motility. (PsycINFO Database Record (c) 2006 APA, all rights reserved)