Subject. Individualized etiotropic prevention of caries in children using bacteriophages. The goal is to study the peculiarities of the carioprophylactic effect of bacteriophages that are part of the drug "Fagodent." Methodology. The study involved 30 somatically safe children of 7―12 years of age with equal gender distribution and a decompensated caries course. The intensity of caries was determined by the formula KPU+CP. Patients with confirmed cariogenic bacteria dysbiosis were selected according to the CRT-bacteria test (Ivoclar company) at CFU/ml≥105. The method involves the collection of stimulated saliva, inoculation and incubation in a thermostat at a temperature of 37 °C for 2 days, the analysis of the number of colonies on a standard scale. The Green―Vermillion Hygiene Index (OHI-S) was also taken into account with an average of 0.9, children with high rates were excluded from the study. Results. After the course administration of the drug, the colonization rate of the oral cavity with cariogenic microorganisms decreases, which is reflected in the decrease in the Green―Vermillion (OHI-S) hygiene indices from 0.9±0.14 to 0.5±0.1 (p<0.05) and the test CRT-bacteria (Ivoclar Vivadent) CFU / ml from ≥105 to ≤105 (p<0.05). Upon further observation, within 3 months after the course of phagotherapy, the levels of contamination of the oral cavity with cariogenic microorganisms and hygiene were reliably kept low. Hygienic indicators also changed after the administration of the drug “Fagodent”: the Green― Vermillion hygiene index significantly decreased from 0.9±0.14 to 0.5±0.1 after 2 weeks and to 0.7±0.1 after 3 months. Findings. Clinical studies have proven the effectiveness of the drug "Fagodent" based on bacteriophages in the complex treatment and prevention of dental caries. The proposed scheme for the individual use of the drug under the supervision of a doctor does not require special equipment, is simple to implement and shows high positive results, which allows us to recommend it for the prevention of caries in children.