The scientific documentation for fluorouracil-based chemotherapy in patients with colorectal cancer has increased during recent years, both for the adjuvant primary situation and in recurrent and metastatic disease. In the case of operable colorectal cancer (stage Dukes B and C), the patients should be included in the ongoing randomized trial on use of fluorouracil and levamisol. In advanced disease, fluorouracil combined with calcium folinate may have palliative effects in terms of relief of symptoms, improved quality of life, delay of onset of symptoms and probably also prolonged survival in 40-50% of the patients, without serious toxicity. In many cases, however, the patient should not be given chemotherapy.