Recent clinical studies have suggested that the combination of subcutaneous recombinant human interleukin 2 (rIL-2) and interferon alpha (rIFN-alpha) is especially promising in advanced renal cell carcinoma. We assessed the safety, activity and toxicity of home therapy with these two agents in 50 patients. Each treatment cycle consisted of a 2 day pulse phase, with 9 x 10(6) IU m-2 of rIL-2 being given subcutaneously every 12 h, followed by a 6 week maintenance phase during which rIL-2 1.8 x 10(6) IU m-2 was administered subcutaneously every 12 h on days 1-5 and rIFN-alpha 2b 5 x 10(6) IU m-2 once a day on days 1, 3 and 5. Objective responses (CR+PR) occurred in 9/50 (18%) patients, six of whom (12%) achieved a complete response. Disease stabilisation was observed in 17 cases (34%) and 18 patients progressed during therapy. In the other six cases, treatment was interrupted early for toxicity or patient refusal. One patient died of myocardial infarction during the second cycle. The overall median survival was 12 months. Home therapy with subcutaneous rIL-2 + rIFN-alpha 2b proved to be active, feasible and moderately toxic, but serious adverse events can sometimes occur.