Aim. To evaluate the efficacy and tolerability of antibiotic therapy in patients with pelvic inflammatory disease during the use of a fixed combination of butyric acid and inulin (Zakofalk) as an adjuvant therapy. Materials and methods. The study included 60 patients with inflammatory diseases of the pelvic organs who underwent antibiotic therapy. The diagnosis was confirmed by an objective examination, ultrasound of the pelvic organs, the results of a smear from the cervical canal. After inclusion in the study, the patients were randomized into 2 groups: the main group received standard antibiotic therapy and Zakofalk, the control group received only standard antibiotic therapy. Results. The incidence of dyspeptic symptoms in the first week of observation in the main and control groups did not differ significantly. When comparing the severity of antibiotic-associated side effects in the second week of observation, statistically significant differences (p0.01) were found in terms of: bloating, rumbling, stools up to three times a day, which were more common in the control group. In addition, a more significant decrease in the level of leukocytes in the cervical mucus was recorded in the main group compared to the control group. The absence of pathogenic and opportunistic pathogens in the first control study, in comparison with the primary diagnosis, was also more pronounced in the main group. Adherence to treatment in the control group, 3.8 points on the MoriskyGreen scale insufficiently adherent, was lower than in the main group 5 points compliant. Conclusion. The inclusion of Zakofalk as an adjuvant drug in the antimicrobial therapy regimen for pelvic inflammatory diseases improves the tolerability of this type of treatment, prevents the aggravation of symptoms of idiopathic antibiotic-associated diarrhea, increases the effectiveness of eradication of the pathogen and contributes to the normalization of the vaginal microbiota.