Between April 1986 and May 1989 a multicentre study was conducted to evaluate the efficacy of a 4-h intravenous infusion of 1000 mg/m2 5-fluorouracil (5-FU) followed by a 1-h infusion of 25 mg/m2 cisplatin (CDDP) given for 4 consecutive days every 4 weeks to patients with advanced squamous-cell carcinoma of the head and neck. A total of 189 consecutive patients entered the study, including 106 who had previously undergone chemotherapy and 83 who were chemotherapy-naive. Of the 165 evaluable patients, 96 (58%) responded to treatment, including 22 (13%) who achieved a complete remission (CR). In the group of previously untreated patients an objective response (CR+PR) was seen in 78% (CR, 14%) whereas in pretreated patients the response rate (CR+PR) was 40% (CR, 13%). The median survival period was 10 months. No significant difference in the duration of survival or of remission was found between the two groups in relation to previous therapy, tumour localisation, disease stage or performance status. Almost half of the patients (49%) experienced leucopenia but it was severe in only 11% of cases. Anemia (mainly WHO grades 1-2) occurred in 38% of the patients. Nausea and vomiting were common (84%). Nephrotoxicity (23%) was mild and of short duration. Moderate hair loss was seen in 42% of the patients, and phlebitis occurred in 8%. A few cases of cardiotoxicity and neurotoxicity were observed. This regimen is well tolerated and can be given even on an outpatient basis. The resultant response rate and side effects appear to be similar to those previously reported for combination chemotherapy with CDDP and continuous 5-FU infusion.