Intestinal gas is the most common cause of technically unsatisfactory abdominal ultrasound scans. In the attempt to increase the visualization of abdominal organs, many investigators use antifoaming agents or laxatives. In the present, randomized, placebo-controlled, double-blind trial, a liquid dimethicone preparation and an extract of senna, alone and in combination, were tested as a means to improve scan quality. Response variables were defined on the basis of pancreas, aorta, and kidney visibility. There was no difference in the response variables of the three groups compared to placebo (P greater than 0.3-0.55). The results suggest that neither dimethicone nor senna improves the visibility of abdominal organs in ultrasound examination.