BACKGROUND: Octreotide therapy is effective in controlling severe dumping symptoms during short-term follow-up but little is known about long-term results. AIM: To report on the long-term results of patients with severe dumping syndrome treated at the Leiden University Medical Center with subcutaneous or depot intramuscular (long-acting release) octreotide. METHODS: Follow-up of 34 patients with severe dumping syndrome refractory to other therapeutic measures treated between 1987 and 2005 with octreotide subcutaneous/long-acting release. At regular intervals symptoms, quality of life, weight, faecal fat excretion and gallstone formation were evaluated. RESULTS: All patients had excellent initial relief of symptoms during octreotide subcutaneous therapy. However, during follow-up 16 patients stopped therapy because of side effects (n = 9) or loss of efficacy (n = 7). Four patients died. Fourteen patients (41%) remain using octreotide (follow-up 93 +/- 15 months), seven are on octreotide subcutaneous and seven on octreotide long-acting release. Patients with severe dumping (both early and late) do better on subcutaneous than long-acting release despite the inconvenience of frequent injections. Dumping symptoms are reduced by 50% even in long-term users. Body weight continues to increase during therapy despite more pronounced steatorrhoea. CONCLUSION: The long-term the efficacy of octreotide is much less favourable compared with short-term treatment.