The Efficacy of Sodium Butyrate and Probiotics in Patients With Irritable Bowel Syndrome

Inclusion Criteria: 1. Males and females aged from 18 to 70 years, inclusive; 2. Good physical and mental condition assessed based on the patient's history and physical examination; 3. Laboratory test results (complete blood count, blood chemistry panel) within normal limits or considered not to be clinically significant by the Investigator; negative SARS-CoV-2 antibody test; 4. A voluntarily provided written informed consent; 5. Diagnosis of IBS based on the Rome IV criteria, e.g. recurrent abdominal pain at least one day a week for the last three months, associated with two or more of the following symptoms (these should be present for the last three months, with the onset of symptoms six months before diagnosis): * related to defecation * associated with a change in stool frequency and/or * associated with a change in stool form (appearance) Patients with any of the following forms of IBS will be included: * IBS-D - more than 25% of BSF type 6 and 7 stools, and less than 25% of type 1 and 2 stools. * IBS-C - more than 25% of BSF type 1 and 2 stools, with less than 25% of type 6 and 7 stools. * IBS-M - more than 25% of BSF type 6 and 7 stools and also more than 25% of type 1 and 2 stools. * at least moderate symptom severity defined as an IBS-SSS score of \>175 (5 items, maximum score 500). 6. The following medications are allowed during this study, provided they have been used at a stable dose and for at least 1 month prior to the study: 1. contraceptive pills or intramuscular contraceptives, 2. hormone replacement therapy (estrogen/progesterone), 3. L-thyroxine, 4. antidepressants at low doses (up to 25 mg of amitriptyline, nortriptyline, or selective serotonin reuptake inhibitor per day) 5. antihypertensives at low doses (diuretics, angiotensin converting enzyme inhibitors angiotensin receptor antagonists). Exclusion Criteria: 1. Unclassified IBS; 2. Cardiovascular disorders: uncontrolled hypertension (blood pressure \>170/100 mmHg), cerebrovascular disease; 3. Respiratory disorders (asthma, chronic obstructive pulmonary disease \[COPD\]). 4. Hepatic impairment (including status post cholecystectomy), renal impairment, and unexplained blood biochemistry abnormalities: serum creatinine levels over twice the upper limit of normal, AST or ALT levels over twice the upper limit of normal. 5. Gastrointestinal conditions other than IBS, including clinical or endoscopic diagnosis of gastroenteritis. 6. Endocrine disorders, including diabetes mellitus (fasting blood glucose \>11 mmol/L) and elevated TSH levels. 7. Severe neurological conditions, with psychosis; 8. Malignancy; 9. Pregnancy or breastfeeding; 10. Hypersensitivity to soy; 11. Lactose intolerance; 12. The use of gastrointestinal motility stimulants or dietary fiber supplements during the 2 weeks preceding the clinical study; 13. The use of antithrombotic drugs; 14. A surgical procedure scheduled during the course of the clinical study; 15. Current probiotic use and refusal to undergo a 3-month washout period; 16. Antibiotic therapy during the 3 months preceding the study; 17. Antibiotic use during the study; 18. Being included in another clinical study during the previous 3 months; 19. History of alcohol or substance; 20. Inability to strictly adhere to the Investigators' instructions regarding study procedures and protocol requirements.abuse.