Thirty-nine patients with head and neck cancer were entered into Phase I-II study of simultaneous radiation therapy with continuous infusion fluorouracil at 800 mg/m2/day and escalating doses of hydroxyurea. Twenty of these patients had recurrent disease after previous surgery and/or radiation therapy (group 1). Nineteen patients had not received prior local therapy but had advanced-stage disease (group 2). Cycles were repeated every other week until the completion of radiation therapy. The median follow-up was 32 months. Patients with recurrent disease were generally treated with palliative doses of radiation (median dose 5,000 cGy) while previously untreated patients received radiation with curative intent (median dose 7,040 cGy). The response rate for 15 evaluable patients with recurrent disease was 93% with 40% of patients achieving a complete response. For 17 evaluable patients without recurrent disease the response rate was 100%, with a complete response rate of 71%. This regimen exhibited a high activity and significant palliative benefit in group 1 patients. However the local control rate was 25% (5/20) because the majority of patients in this group eventually developed a local recurrence. The local control rate for group 2 patients was 84% (16/19). The higher local failure rate in group 1 patients appeared to be attributable to the palliative doses of radiation delivered and the fewer cycles of treatment received. We conclude that this regimen has palliative benefit in patients who have failed prior local therapy and has the potential for cure in patients with poor prognosis advanced stage disease as well.