Thirty-three patients with advanced colorectal cancer were entered on a phase II study of 4'-deoxydoxorubicin (esorubicin) (30-35 mg/m2 q 3 weekly). Objective response was documented in 4 of 25 previously untreated patients and in none of 8 previously treated patients. Toxicity was acceptable with grade 3 or 4 leukopenia occurring in 8 patients. Complete alopecia occurred only in 4 patients and gastro-intestinal toxicity was mild. A significant decrease (greater than 10%) of the left ventricular ejection fraction occurred in 8/23 patients who received greater than 2 courses of treatment.