Multiple or recurrent squamous cell skin carcinoma is a rare tumor in the aged. These patients are currently treated with 5-fluorouracil (5-FU) cream as a local chemotherapy; in cases in which the disease progresses, few treatments are available. Two reports deal with the treatment of progressive squamous cell skin carcinoma with systemic 5-FU, but in only eight patients age less than 70 years. We prospectively investigated oral 5-FU therapy in 14 consecutive patients (average age 76 1/2 years) with histologically proven squamous cell skin carcinoma. The disease was aggressive, multiple, or recurrent and had not been eradicated by surgery, radiation therapy, topical 5-FU cream, and non-5-FU chemotherapy. Oral 5-FU was administered as mannitol-coated 5-FU tablets at the daily dose of 175 mg/m2 for 3 weeks every 5 weeks. Toxicity, effectiveness, quality of life, and compliance to therapy were evaluated. Total cycles amounted to 55 (range: 2-6, mean: 4 for each patient) at an average dose intensity of 740 mg/m2/week for from 12 to 36 weeks. Only gastrointestinal toxicity World Health grade I occurred. Quality of life and compliance to therapy were 90%. Therapy induced measurable improvement in nine patients (64.3%): two partial remissions (14.3%), three minimal remissions (21.4%), and four arrests of disease (28.6%) with a median duration of 30+ months. The study ended because of a lack of patients. We can conclude that, if elderly patients require chemotherapy because of progressive multiple or advanced squamous cell skin carcinoma, appreciable results may be obtained with oral 5-FU as a single agent.