OBJECTIVES: I. Assess the toxicity profile of irinotecan and amifostine when administered together in patients with metastatic colorectal cancer. II. Assess the total dose of irinotecan received per 6 week course in these patients. III. Determine the incidence of irinotecan-induced leukopenia, neutropenia, and diarrhea in these patients. V. Determine the response rate for this patient population.