Fourteen patients with metastatic renal cell carcinoma (RCC) were treated with high-dose folinic acid (HDFA): 200 mg/m2 i.v. and 5-fluorouracil (5-FU): 370 mg/m2 i.v. for 5 consecutive days every 28 days. Severe oral mucositis (WHO grade III-IV) was experienced by two patients, whereas hematological toxicity was mild. No complete or partial remission was observed. Short-lasting stable disease occurred in 8 patients (median = 5 months, range 2-11). This combination does not need further evaluation in patients with RCC.