Anguidine was administered in a dose of 5.0 mg/m2 (3.5 mg/m2 for patients with hepatic dysfunction) intravenously daily for 5 days in a phase II evaluation of 19 patients with metastatic adenocarcinoma of the colon or rectum. Courses were repeated every 3 weeks. No responses were observed but five patients had disease stabilization. Toxicity was marked, causing discontinuation of therapy in several patients. Anguidine appears ineffective in patients with metastatic colon or rectal cancer in the dose and schedule used in this study.