The clinical and laboratory effectiveness of a biocomplex of probiotic bacteria (Bifidobacterium BB-12, Streptococcus thermophilus TH-4) in preventing the development of microecological and gastrointestinal disorders in children born by cesarean section has been studied. A prospective open comparative study was conducted. The main group consisted of 16 healthy newborns born by cesarean section who were treated with a probiotic (Bifidobacterium BB-12, Streptococcus thermophilus TH-4) at 1 dose once a day. Oral administration of the probiotics began immediately after delivery and continued for 14 days. A control group of 21 healthy babies born by caesarian section who did not receive the probiotics during the study period was also included. Bacteriological analysis of fecal samples and assessment of the health status were performed at the ages of 4–5 days, 1 month, and 3 months. In children receiving probiotics, the incidence of infantile intestinal colic was lower at the age of 1 month, opportunistic microflora were less frequently isolated (p<0.01), and signs of inflammation in the intestines were less often detected during the follow-up period, as shown by a coprological study.Conclusion. The effectiveness of using probiotics (Bifidobacterium BB-12 and S. thermophilus TH-4) to prevent microecological and gastrointestinal problems in children born by cesarean section has been demonstrated.