Having a large selection of probiotics on the pharmaceutical market requires doctors to know all the possible biological effects of these drugs. Lactobacillus reuteri has antimicrobial action against pathogenic bacterial species, viruses, fungi, anti-inflammatory, immunomodulatory, detoxifying effect, acid resistance, promotes the restoration of intestinal microbiota. L. reuteri B-9448 is one of the most accessible and effective strains in the formulations of modern probiotics used for the prevention and correction of various conditions and diseases. The biologically active additive "Reuteri ECOlab", which combines the unique properties of living L. reuteri bacteria, highly active products of their metabolism and MCT oil, allows the drug to be used in combination therapy of acute diarrhea in children and adults, rotavirus infections, eradication of Helicobacter pylori infections, antibiotic-associated diarrhea, functional abdominal pain and allergic reactions in children. The form of administration in the form of drops, the absence of alcohols, emulsifiers, flavors, preservatives and dyes in the composition, the absence of the risk of overdose make the use of "Reuteri ECOlab" not only effective, but also convenient and safe.