[Action of ftorafur and 5-fluorouracil on the chromosomes of normal and tumorous cells in vivo].

No chromosome aberrations were found in the bone marrow cells and Djungarian hamster tumor cells and bone-marrow cells of thymectomized mice receiving different doses of fluorafur and 5-fluoruracil in vivo. The time of exposure to these antitumor drugs varied from 2 to 72 hours. 12% of aberrant metaphases under 400 mg/Kg of fluorafur and 38%--under 200 mg/Kg of 5-fluoruracil were found in cells of human colonic tumor trasplanted into thymectomized mice.