In this study researchers want to learn more about the effectiveness of Iberogast® in patients with irritable stomach and concomitant chronic or recurrent heartburn and backward flow of stomach liquid into the esophagus. 60 patients in the age range from 18 - 80 year will be treated over 4 weeks with Iberogast® or placebo - an inactive substance which looks identical to Iberogast®. Patients completed diaries will provide researchers with detailed information on the change of stomach and intestinal symptoms during the treatment period. In addition information on the acidity of the esophagus and stomach liquid will be collected.

Inclusion Criteria:

1. Patients of either sex aged 18-80 years.

2. Diagnosis of functional dyspepsia according to Rome III criteria:

   • Pain or burning localized to the epigastrium of at least moderate severity at least once per week with a total duration of at least 6 months.
   • Pain was intermittent.
   • Pain was not generalized or localized to other abdominal or chest regions.
   • Pain was not relieved by defecation or passage of flatus.
   • Pain did not fulfil criteria for gallbladder and sphincter of Oddi disorders.

3. At assessment (visit 1 or 3) three items of GIS had to be judged at least as moderate including reflux symptoms, but reflux symptoms not dominating the clinical picture.

4. Endoscopy of the upper gastrointestinal tract and abdominal sonography without pathological findings that could have explained the symptoms (findings of up to 5 gastric erosions could be tolerated if patient had no concomitant intake of acetylsalicylic acid).

5. Patients willing to comply with the study protocol.

6. Patients who were able to understand and provide written informed consent to participate in the trial (signed informed consent).

Exclusion Criteria:

1. Concomitant treatment during the study with any medication that could influence the gastrointestinal function (e.g. prokinetics, antacids, antibiotics, antidepressant, laxatives, calcium antagonists, beta-blocker, antidiarrheics).
2. Regular intake of nonsteroidal antiphlogistic drugs incl. cyclooxygenase-2 (COX-2)-inhibitors (exception: acetylsalicylic acid for cardiovascular prevention up to 100 mg daily).
3. History of clinically relevant gastrointestinal disease such as gastric-, pancreatic-, colon-, rectal-cancer.
4. History of gastric and/or duodenal ulcer.
5. History of abdominal surgery (cholecystectomy and appendectomy could be tolerated).
6. History and/or presence of coronary heart disease.
7. Known intolerance to azo dyes E 110 and E 151.
8. Food allergies and known lactose intolerance.
9. Evidence of any gastrointestinal infectious diseases.
10. Participation in a clinical trial 30 days prior to this trial.
11. Concurrent participation in another clinical trial.
12. Female patients of childbearing potential with a positive pregnancy test, breast feeding, or female patients of childbearing potential without adequate contraception.
13. History and/or presence of drug or alcohol abuse.
14. Patients with psychiatric illness.
15. Irritable bowel syndrome.

Availability of this study's data will be determined according to Bayer's commitment to the EFPIA/PhRMA "Principles for responsible clinical trial data sharing". This pertains to scope, timepoint and process of data access. As such, Bayer commits to sharing upon request from qualified researchers patient-level clinical trial data, study-level clinical trial data, and protocols from clinical trials in patients for medicines and indications approved in the US and EU as necessary for conducting legitimate research. This applies to data on new medicines and indications that have been approved by the EU and US regulatory agencies on or after January 01, 2014. Interested researchers can use www.clinicalstudydatarequest.com to request access to anonymized patient-level data and supporting documents from clinical studies to conduct research. Information on the Bayer criteria for listing studies and other relevant information is provided in the Study sponsors section of the portal.