One hundred and thirteen patients with advanced squamous cell cancer of the head and neck were entered into a multicenter trial. Median age was 54 yr (range: 33-74 yr). Median Karnofsky index was 70 (60-100). Thirty-five patients had had prior induction chemotherapy. The first schedule was carboplatin 300 mg/m2, dl and fluoro-uracil 1000 mg/m2/d administered in continuous IV infusion for 96 h every 4 weeks (group 1). The second schedule was carboplatin 350 mg/m2, dl and fluoro-uracil administered at the same dose every 3 weeks (group II). Median number of cycles was 3 (range: 1-16). Seven patients were not eligible. The response rate was 26% (95% confidence limits: 18-34). Nine patients had a complete response. The median duration of response was 6 months (2-16+). The response rates in the 2 groups were not statistically different (21 and 31%) but disease progression was more frequent in group I (61%) than in group II patients (25%). Six early deaths occurred, without sign of drug toxicity. Grade 2 hematological toxicity between or before any cycle was more frequent in group II patients, in particular for leucopenia (13 vs 42%, P less than 0.05). One death was related to granulopenia. Grade 2 or 3 gastric toxicity was observed in 43 patients. No other major toxicity was observed. In our study, combination therapy with carboplatin and fluoro-uracil was found to be moderately active but myelotoxic.