Objective Currently, probiotics are increasingly used as the alternative to antibiotics as well as the preventive measures in humans. In particular, probiotics occupy a key position in the treatment of antibiotics-associated intestinal dysbiosis. A spore-forming microorganism lactobacillus Bacillus coagulans is one of the most promising probiotics. However, some of its pharmacological effects remain poorly understood. Aim. This study is aimed at investigation of the effect of Bacillus coagulans (Laktovit Forte) on the intestinal dysbiosis syndrome in mice caused by streptomycin against the background of cyclophosphamide-induced cellular immunodeficiency. Methods. Pharmacological method: mouse model in vivo with immunodeficiency caused by cyclophosphamide. Key findings. In mice with colitis caused by streptomycin treatment, the administration of Bacillus coagulans (Laktovit Forte medicinal product) resulted in an antidiarrheal effect, normalization of gastrointestinal motility, and prevention of the animals weight loss. Given the cyclophosphamide-induced immunosuppression and streptomycin-associated diarrhoea, the immunity was completely restored only under the action of Bacillus coagulans. Conclusions. According to all parameters, Bacillus coagulans has been proved to be more effective as compared to the Linex Forte reference product containing lacto- and bifidobacteria.