Purpose of the study:

To obtain additional data on efficacy and safety of Kolofort in the treatment of patients with functional dyspepsia.

Design: a multicenter double-blind placebo-controlled randomized clinical trial to evaluate the efficacy and safety of the study treatment.

The study will enroll the patients of both genders aged 18-45 years old with verified diagnosis of "functional dyspepsia" according to Rome-IV criteria and intensity of dyspeptic symptoms ≥ 6 according to GIS (Gastrointestinal symptom score).

At the screening visit 1 (Visit 1, from -14 to -1 days), after signing patient information sheet (informed consent form) to participate in the clinical trial, complaints and medical history are collected, an objective examination is performed. The investigator evaluates intensity of dyspeptic symptoms according to GIS. The patient undergoes an abdomen ultrasound examination, esophagogastroduodenoscopy (EGDS) , and diagnostic tests for Helicobacter pylori (H. pylori) infection. In case of the previous use of proton pump inhibitors, prokinetics, antispasmodics, antacids, bismuth drugs the investigator evaluates the possibility of canceling these drugs at least 7 days before the patient is randomized. For women of reproductive age, a pregnancy test is performed.

On the day of randomization (Visit 2, Day 0) collection of complaints and objective examination are carried out. The investigator evaluates the results of laboratory and instrumental research methods, the severity of dyspepsia symptoms on the GIS scale, registers changes in concomitant therapy.

If a patient meets all inclusion criteria and does not have any exclusion criteria, he/she is randomized into one of two groups: patients in Group 1 receive Kolofort for 8 weeks; patients in Group 2 - Placebo on the study drug regimen. The patient completes the Nepean Dyspepsia Index (NDI) and Quality of Life (SF-36) questionnaires.

The patient's treatment lasts for 8 weeks, during which 3 visits to the research center are carried out. At Visit 3 (Week 2 ± 3 days), complaints are collected, an objective examination of the patient is performed. The investigator monitors the prescribed and concomitant therapy, evaluates the safety of therapy and the degree of adherence to treatment (compliance). At visit 4 (week 4±3 days) and 5 (week 8±3 days) the investigator collects complaints, registers the physical examination data, monitors the prescribed and concomitant therapy, assesses the safety of the treatment and compliance. Questionnaires GIS, NDI are filled in.

Additionally, at Visit 5 the patient fills out the SF-36 scale, the investigator fills out the Clinical Global Impression-Efficacy Index (CGI-EI).

The patients will be allowed to take symptomatic therapy and medications for their co-morbidities during the study, except for the medicines listed in "Prohibited Concomitant Treatment".

Inclusion Criteria:

1. Patients of both genders aged 18-45 years old.
2. Diagnosis of functional dyspepsia established according to Rome-IV criteria (2016).
3. Severity of symptoms of dyspepsia ≥ 6 on the GIS scale.
4. Negative test result for H. pylori infection .
5. Availability of signed patient information sheet and informed consent form for participation in the clinical trial.
6. Patients who gave their consent to use reliable contraception during the study

Exclusion Criteria:

1. Organic diseases of the gastrointestinal tract (gastroesophageal reflux disease (GERD), peptic ulcer, chronic pancreatitis, cholelithiasis, hepatosis, hepatitis, hepatic cirrhosis, etc.)
2. Verified diagnosis of other functional GI diseases, i.e. biliary dyskinesia, irritable bowel syndrome, etc.
3. Discontinuation of proton pump inhibitors, prokinetics, antispasmodics, antacids, bismuth preparations less than 7 days before randomization.
4. H. pylori eradication within 2 months prior to enrollment.
5. Intestinal infection within 2 months prior to enrollment.
6. History/suspicion of oncology of any location.
7. Previously diagnosed cardiovascular diseases with functional class IV (according to the classification of the New-York Heart Association, 1964), hypothyroidism, diabetes mellitus, chronic renal disease С3-5, hepatic diseases with portal hypertension and/or signs of severe decompensation of function (> 6 points according to the Child-Pugh classification).
8. Any other severe comorbidity that, in the opinion of the investigator, may affect patient participation in the clinical trial.
9. Allergy/intolerance intolerances to any of the components of the study drugs.
10. Pregnancy, breast-feeding.
11. Patients who, from the investigator's point of view, will not comply with the observation requirements of the study or adhere to study drug dosing regimens.
12. Scheduled hospitalization during the study for any diagnostic or therapeutic procedures.
13. Use of drugs or alcohol (more than 2 alcohol units daily), presence of mental diseases.
14. Use of any medications specified in the "Prohibited Concomitant Treatment" within 1 month prior to inclusion in the study.
15. Participation in other clinical trials in the previous 3 months.
16. Patients who are related to any of the on-site research personnel directly involved in the conduct of the trial or are an immediate relative of the study investigator. 'Immediate relative' means husband, wife, parent, son, daughter, brother, or sister (regardless of whether they are natural or adopted).
17. Patients who work for MATERIA MEDICA HOLDING (i.e. the company's employees, temporary contract workers, appointed officials responsible for carrying out the research or immediate relatives of the aforementioned).