The effects of drug treatment and of cold-restraint stress (a method used to produce experimental stomach ulcers) on gastric emptying of a resin (colestipol-phenol red complex) were investigated in rats. Gastric emptying was decreased by intraperitoneal treatment with atropine (0.3 mg/kg) or verapamil (4 mg/kg), and enhanced by bethanechol (1.2 mg/kg). Stress by restraint at 4 degrees C for 2 hr markedly reduced gastric emptying; the pattern of effects of drug pretreatment in these stressed rats was similar to that seen in their nonstressed controls. Further experiments, with stress for 3 hr, revealed that the gastric emptying rate was triphasic; increasing in the first hr, returning to normal and then slowing in the third hr of stress. Initial increase in emptying rate was probably due to predominant vagal overactivity. Hypothermia and possibly other factors induced by cold-restraint stress could have subsequently depressed gastric motility.