Thirty-four patients with advanced (stage IV) or relapsing squamous cell carcinoma of the head and neck (SCC-HN) were treated alternately with chemotherapy (CT) and radiotherapy (RT). Patients' characteristics were as follows: male: female ratio, 27:7; median age, 55 (34-76), median P.S., 1 (ECOG scale) (range 0-2). Patients studied had no renal, hepatic, or cardiac impairments, a life expectancy of greater than or equal to 3 months, and no previous treatment with RT or CT. Seventeen patients were previously untreated, and 17 had a relapse after radical surgery. The CT regimen consisted of 20 mg/m2 cisplatin, with 2 h forced diuresis, from day 1 to 5, and 200 mg/m2 i.v., from day 1 to 5, every 3 weeks, administered four times. The RT was performed after the first, second, and third CT course, and consisted of three courses of 20 Gy each, 2 Gy daily, 5 days per week. Weekend intervals were planned between CT and RT treatments. The 17 previously untreated patients showed an overall response rate of 88.2% [eight complete response (CR), seven partial response (PR), one stable disease (SD), one progression disease (PD)]; the 17 patients treated at relapse after radical surgery reached an overall response rate of 64.7% (six CR, five PR, six PD). Actuarial median survival is 47 weeks: 51 weeks in untreated patients, and 42 weeks in previously treated patients. Toxicity was mild, and only 10 patients suffered from grade III (WHO scale) gastrointestinal (2 patients), hematological (5 patients), mucosal (2 patients), and neurological (1 patient) toxicity. Neither grade IV toxicity nor treatment-related deaths have been observed. In our study, cisplatin and 5-FU alternating with RT has shown an interesting antitumor activity and moderate side effects.