A pilot study of continuous infusional 5-fluorouracil 200 mg m-2 per 24 h by ambulatory pump and Hickman line for the entire treatment cycle with mitomycin C 8 mg m-2 i.v. on day 1 and cisplatin 75 mg m-2 i.v. on day 1, both repeated every 28 days, was carried out in 31 previously untreated patients with advanced non-small-cell lung cancer (NSCLC). Of 31 patients assessable for response, one attained a complete remission and eight a partial remission, an overall response rate of 29%. Haematological toxicity was minimal, with only 3% of patients developing WHO grade III/IV neutropenia and 13% grade III/IV thrombocytopenia. Significant side-effects included moderate to severe emesis (41%), mucositis (34%), diarrhoea (31%) and palmar-plantar syndrome (14%). Seven patients (23%) had Hickman line complications requiring line removal. Continuous infusional chemotherapy with this regimen is active in advanced non-small-cell lung cancer, but its complexity and associated treatment toxicity offer little advantage over equally active but simpler and less toxic cisplatin-based regimens.