Docetaxel (Taxotere), a new semisynthetic taxoid, is a potentially important chemotherapeutic agent for the treatment of cancer. Forty patients with bidimensionally measurable advanced adenocarcinoma of the colon were treated with docetaxel 100 mg m-2 every 3 weeks as a 1 h infusion without routine premedication. Thirty-nine patients were eligible: 23 males and 16 females. Median age was 60 years (range 41-75) and WHO performance status 1 (0-2). Prior adjuvant chemotherapy was performed in four patients and prior radiotherapy in nine patients. Bidimensionally measurable disease sites included: liver in 26 patients, lymph nodes and abdominal/peritoneal masses in 13, lung/mediastinal masses in ten and subcutaneous nodes in four. The median number of cycles given was 2 (range 1-15). Thirty-three patients were evaluable for response. One patient (3%) achieved a complete response and two (6%) (95% confidence limits 0-14%) a partial response. Side-effects were similar to those observed in other studies. Docetaxel, given at this dosage and schedule, has minimal activity in the treatment of colorectal carcinoma.