<p>New antineoplastic preparations К-26 and К-26-w have been created on a basis of alkaloid colchicines, which were studied in animals with common tumors in comparison with commercial preparations taxol, vincristine and etoposide, and also with earlier developed derivatives colchicine and colchamine К-19 and decovine. The experiments were conducted on 60 outbred mice with Ehrlich’s solid tumor and the Sarcoma 180 and in 32 outbred rats with Carcinosarcoma Walker. All drugs are administered in therapeutic doses 8-fold mode on the 10th day and on the 3rd day after tumor subinoculation. Estimated results are obtained according to standard provisions. A study of preparations К-26 and К-26-w in animals with tumors has revealed their more expressed activity compared to taxol, vincristine and etoposide; the activity of these preparations is 4-10% lower than the actions К-19 and dekovine, but causing a decrease in the number of leukocytes. The lower level of side effects is explained by the greater ability to induce К-26 compared to К-19 and dekovine..</p>