26 patients with progressive neuroendocrine tumours received 3 x 10(6)U/m2 interferon alfa (IFN-alpha 2b) subcutaneously thrice weekly, until progression, as outpatients with moderate toxicity. 4/16 carcinoids and none out of 10 endocrine pancreatic tumours showed objective regression. Another 17 patients (68%) had no change. For a median of 34 weeks symptom control was excellent: 9 of 17 patients had major relief from pain, 11 of 13 from diarrhoea, and 7 of 7 from flushing. Thus, low-dose INF-alpha 2b given thrice weekly might be as effective as daily treatment with higher dosages. Treatment was only administered to patients with progression or major symptoms and this did not seem to adversely affect remission quality and survival.