A total of 48 patients suffering from rectum cancer were included in this randomized study conducted at the Proctology Department of the Donetsk Regional Anti-Cancer Center. Patients in group I (24 patients) received an intensive course of high fractional X-ray therapy (cumulative dose up to 25 Gy) with direct protracted endolymphatic chemotherapy with 5-fluorouracil (5-FU) instilled in 600 mg/m2 each day before operation, up to a cumulative dose of 5 g. The 24 patients in group II were treated with Ukrain as monotherapy, 10 mg each second day before operation (up to a cumulative dose of 60 mg) and a total of 40 mg after surgical intervention. Repeated Ukrain courses (100 mg/per course) were also given 6 months after surgical operation. In each ease preoperative treatment was followed by routine surgical operation. Prolongation morbi were found to have developed 14 months later in six patients in group I (25.0%), whereas in group II they were found only in two cases (8.3%). Comparative investigation of objective and subjective signs, analysis of results of instrument and X-ray data, as well as dynamic study of the histological structure of rectal tumors, indicate that Ukrain exerts a more potent malignotoxic and immunomodulating action than other types of anticancer treatment.