One hundred and eight patients with squamous cell carcinoma of the upper aerodigestive tract (UADT) (T3, T4, NO-N3; 17% stage II, 54% stage III, 27% stage IV) were given three courses of chemotherapy before any local treatment. The regimen consisted of cis-platinum 100 mg m-2 on day 1 and 5-fluorouracil 1000 mg m-2 on days 2-6; drugs were administered by continuous infusion. The toxicity of this protocol was acceptable, as 82% of the patients were able to receive the initially scheduled drug dose. The overall response rate of 86.5% included a 35% rate of complete lesion regression. The effect of this regimen on primary tumours was especially remarkable--87.5% responses, including 47.5% complete responses. Results for lymph node metastases were not as good--66% responses, including 33% complete responses. The best results were obtained for tumours of the oropharynx and hypopharynx; oral cavity lesions were the most refractory. For those patients who were subsequently operated on, histological examination of the surgical specimen either confirmed sterilization or demonstrated the persistence of small disease foci. After local treatment, which consisted of radiotherapy alone for 69% of patients, the lesion control rate was 80%. At 18 months follow-up, the survival rate for patients who achieved a complete response with chemotherapy was significantly better than that for patients with a response of less than 50%.