OBJECTIVES: I. Determine the maximum tolerated dose and the dose limiting toxicities of irinotecan in patients with progressive or recurrent malignant glioma. II. Define the safety profile of every 3 week dosing of irinotecan in these patients. III. Characterize the pharmacokinetic profile of this regimen in these patients. IV. Assess evidence of antitumor activity in these patients. V. Determine the efficacy of irinotecan in these patients as measured by 6 month progression-free survival and objective tumor response. VI. Evaluate further the safety profile of irinotecan in these patients during phase II study.