Ninety six colorectal carcinoma patients were included in a randomised study, 48 were treated with Ukrain monotherapy (15 with metastatic and 33 with nonmetastatic colorectal carcinoma) and 48 with 5-fluorouracil (5-FU) and X-ray therapy (the same randomised groups). The results of therapy including clinical, haematological, immunological and biochemical parameters show that Ukrain has favourable properties in the treatment of colon and rectal cancer as a monotherapy because of its malignotoxic and immunomodulating action. Objective response rate in the group of metastatic colorectal cancer treated by Ukrain was 40%. There was no registered tumour regression in the group treated by 5-FU. Operability is strongly facilitated by pretreatment with Ukrain. The survival rate (up to 21 months) in the Ukrain-treated patients with nonmetastatic colorectal cancer was 78.6% and 33.3% in a corresponding control group. Ukrain is a new effective drug in the therapy of colorectal cancer. It can be useful both for the therapy of metastatic colorectal cancer and for neoadjuvant therapy of nonmetastatic colorectal cancer.