A dual radioisotope technique was used to measure gastric emptying of a mixed liquid and solid meal in 11 patients with bulimia nervosa, and was compared with 10 patients with anorexia nervosa and a sex-matched control population. The relationship of body weight and gastrointestinal symptoms to gastric emptying was also examined. Gastric emptying of solids in patients with bulimia nervosa was similar to that in controls (gastric T1/2 131 +/- 15 min vs 119 +/- 7 min; mean +/- SEM). In contrast, patients with anorexia nervosa had overall delayed emptying (182 +/- 31 min; p less than 0.05); six patients had normal emptying of the solid components of the meal and four had markedly delayed emptying. Gastric emptying of liquids was similar in the bulimics and controls (gastric T1/2 48 +/- 5 min and 49 +/- 4 min, respectively), whereas the anorexics tended to have prolonged gastric emptying (65 +/- 11 min, p = NS). There was no correlation between body weight, gastrointestinal symptoms, and gastric emptying in either group. These findings suggest that gastrointestinal symptoms are unreliable indicators of gastric emptying in patients with eating disorders, and that gastric emptying studies should be performed in such patients before treatment with prokinetic agents is considered.