Xymedon, a new preparation of the pyrimidine series, was studied in experiment and in the clinic. Experiments showed that on the 5th postoperative day the tensile strength of the scar was greater by 57% and the elasticity strength was greater by 21.5% in animals given Xymedon that in the control animals; the tensile strength was 42.4% greater than in animals given methyluracil. Oral administration of Xymedon in the postoperative period in 92 patients with various forms of acute appendicitis allowed earlier removal of the sutures and reduction of the number of wound complications from 13.8 to 3.3%, as a result of which the patients were discharged from the clinic within a shorter period. The authors recommend Xymedon as a stimulator of reparative processes in the wound and for the prevention of postoperative wound suppuration in emergency abdominal surgery.