Aim of our study was to study the preventive and therapeutic effect of microbial products, including dry and freeze-dried live cultures of lactobacillus. The article presents the results of comparative evaluation of the dynamics of clinical data in the prevention in 164 adolescents aged 14 to 18 years, and in the treatment of chronic generalized periodontitis of mild to moderate severity in 100 adults, with the appointment of probiotic in one group. The level of the oral hygiene and the state of periodontal tissues were estimated by the standard dental indieces. It was found that probiotics used in complex of preventive and treatment measures, regardless of the technology of their creation, contribute to positive clinical dynamics, namely to improve oral hygiene and the condition of the periodontal tissues.