The effect of long-term cisapride therapy (20 mg orally three times daily for 2 years) on gastric emptying and gastrointestinal symptoms was investigated in 30 patients with severe gastroparesis (24 idiopathic, 6 diabetic). Symptoms were assessed every 2 months, using an overall symptom score based on six symptoms (anorexia, nausea, vomiting, pain, early satiety and bloating), and a 2-year mean overall symptom score was used for analysis. Gastric emptying was measured at 0, 6, 12, 18 and 24 months. Of the 24 patients who completed the study, 10 showed a significant improvement in gastric emptying (P < 0.05) and felt improved on therapy, seven patients showing a > 20% improvement in overall symptom score compared to baseline. Results for 15 patients who underwent at least one follow-up gastric-emptying test showed only a weak correlation between individual symptom score and gastric emptying (r = 0.40). Thus long-term cisapride therapy at the study dose produced long-term symptomatic improvement in 42% of patients with severe gastroparesis, with sustained acceleration of gastric emptying for up to 2 years.