4'Demethoxydaunorubicin (DMDR), an orally active daunorubicin analogue, was administered to 22 patients with advanced colorectal carcinoma. Patients were stratified into good- and poor-risk categories and received doses of 45 mg/m2 and 40 mg/m2, respectively, at 28-day intervals. Twenty-one patients were evaluable for response. No tumour responses occurred, although six patients had stable disease. Therapy was well tolerated. Mild gastrointestinal toxicity occurred in 45% of patients. Marrow toxicity was common and usually mild. DMDR appears to have no useful activity in colorectal carcinoma.