The activity of carboplatin (CBDCA) was tested in 21 consecutive patients with advanced colorectal cancer that had progressed during fluoropyrimidine therapy. CBDCA was chosen in view of the favourable results obtained in previous phase II studies. We were unable to find any activity of the agent which was given every 21 days at a dose of 400 mg/m2. The main toxicity was haematological. CBDCA is not recommended in pretreated patients with colorectal cancer.