Efficacy and Safety of Sinquanon for Prevention of Antibiotic-associated Diarrhea in Adults

Inclusion Criteria: * Male or female subject aged 18 to 60 years. * The subject has given written informed consent after being provided orally with information about the study objective and design, including the administration regimen of the studied probiotic and the study procedures, the available safety data, as well as the rights and obligations of a participant. * The subject initiates oral antibiotic treatment in the ambulatory setting. * Acceptable antibiotic therapy: * Broad-spectrum penicillins * Cephalosporins * Quinolones * Tetracyclines Sequential administration of two antibiotics from the allowed groups is permitted, if the total duration of the antibiotic treatment does not exceed 10 days. * Planned duration of the antibiotic treatment of 5 to 10 days. * Body mass index (BMI) of 18.0 to 29.9 kg/m2 * In the opinion of the Investigator, the subject can adhere to the visit schedule, to be compliant with the trial treatment regimen and to complete the study. * The patient has a smartphone and can use it. Exclusion Criteria: * Antibiotics use within 60 days prior to randomization. * Daily consumption of probiotics, yogurt with probiotics and inability to stop this consumption. * Use of antidiarrheal medications, laxatives, enemas, or suppositories within 1 week prior to randomization and for the duration of the trial. * An episode of diarrhea within 30 days before screening, defined as ≥3 loose or liquid stools over 24 hours, regardless of the cause of the diarrhea. * Acute or chronic constipation - average number of formed stools \<3 per week. * Allergy or hypersensitivity to any of the ingredients of the trial product. * Allergy or hypersensitivity to the antibiotic prescribed on Day 1. * Prior documented infection with Clostridioides difficile ≤3 months before screening. * History of chronic gastrointestinal conditions, including irritable bowel syndrome, chronic constipation, chronic diarrhea, dyspepsia, gastroesophageal reflux disease, diverticulitis, ulcerative colitis, Crohn's disease or any other abnormality in the absorption or gastrointestinal dysfunction. * Use of proton-pump inhibitors (PPIs) within 30 days prior to Day 1 and for the duration of the study. * Surgery to the intestines, artificial heart valve, history of rheumatological heart disease or infectious endocarditis within one year prior to screening. * Immunosuppressive therapy or any condition causing immunosuppression (including hematologic malignancies, AIDS, long-lasting corticosteroid treatment). * Planned administration of antibiotics, different from those acceptable for the study. * Patients in severe condition requiring urgent hospitalization or planned hospitalization during the study. * Planned administration of antibiotics \>10 days. * BMI ≥ 30 kg/m2. * Pregnant or lactating women; women who plan to get pregnant during the study. * Drug abuse or alcohol within the past year. * Unstable medical conditions, in the judgement of the Investigator. * Eating disorders (for example, anorexia, bulimia). * On a vegan diet. * Participation in a clinical trial within 60 days prior to randomization. * Inability to comply with the study protocol.