Fourteen patients with malignant gliomas were entered on a phase II study of 5-fluorouracil 300-370 mg/m2 plus folinic acid 200 mg/m2 x 5 days q4 weeks. To be eligible, patients could not have received more than 1 prior chemotherapy regimen. A single patient with a recurrent oligodendroglioma responded. Toxicity (predominantly stomatitis, diarrhea, and granulocytopenia) was tolerable and was similar to that seen in studies of 5-fluorouracil plus folinic acid in other tumor types. This regimen has minimal activity in recurrent malignant gliomas.