The parameters of colon microbiocenosis were evaluated in healthy animals belonging to 6 species of marmosets; its disorders typical of patients with different forms of acute intestinal infections were revealed. Bifidoflora of young monkeys was characterized. The study demonstrated multiple similarities of the microflora of monkeys and humans, including small children. A preclinical study of dry bifidin, a probiotic, revealed its advantages over the commercial bifidumbacterin. 90 monkeys were used for preclinical evaluation of complex immunoglobulin preparation (CIP) and a combination of CIP with interferon (kipferon in suppositories). The study demonstrated sanifying and microflora-normalizing effects, increase of anti-microbial antibodies and serum interferon after both parenteral and rectal administration. The protective activity of a new variant of the probiotic Acilact in exposure to ionizing radiation and anticancer chemotherapy under experimental conditions