We conducted a 12-month trial of cisapride (10 mg three times a day) in 21 patients with gastric stasis due to clinically and manometrically diagnosed gastroparesis (N = 9; seven due to diabetes) or chronic intestinal pseudo-obstruction (N = 12). Radionuclide solid-liquid gastric emptying tests were performed at baseline and at the end of the 12-month period. Symptoms were assessed monthly by diary and every three months by the investigators; frequency and severity of symptoms were scored in a standardized manner. For the whole group of 21 patients, gastric emptying of both solids and liquids improved significantly after one year of cisapride (P less than 0.05). Among chronic intestinal pseudoobstruction patients, there was predominantly an improvement in gastric emptying of solids; in contrast, patients with gastroparesis had a greater improvement in liquid emptying. Total symptom score improved significantly in the gastroparesis group (median score: 8 at baseline vs 6 at one year, P less than 0.05) but not in the chronic intestinal pseudoobstruction patients (median score at baseline 10 vs 9 at one year). Similarly, body weight showed a trend towards improvement in the gastroparesis group. No significant side effects were noted. We conclude that during a 12-month open trial, cisapride was effective in improving gastric emptying in patients with gastric stasis and consistently improved symptoms in those with gastroparesis.