Forty-three patients with metastatic melanoma were treated with a 5 day (18 patients) and a 3 day (25 patients) schedule of high-dose IL-2 11.7 MIU m2 and IFN-alpha 3 MIU m2 i.v. by bolus administration every 8 h, repeated every 21 days for a total of three courses. The 5 day schedule resulted in a high response rate of 41% (CI 18-67%), but was accompanied by severe cardiotoxicity (41%) and central nervous system toxicity (28%). The 3 day schedule was associated with manageable toxicity, but yielded a moderate response rate of 20% (CI 7-43%).