Therapeutic Effect of Ursodeoxycholic Acid in Functional Dyspepsia

Inclusion Criteria: Men and women (age 18-60 years) who meet the Rome IV criteria for functional dyspepsia can participate in the study. For 14 weeks, patients need to discontinue their intake of proton pump inhibitors, drugs effecting gastric motility and NSAIDs. If a female participant takes oral anticonception, she has to switch to non-oral anticonception for this study. All participants will receive and sign a copy of the informed consent. Exclusion Criteria: * refused informed consent * pregnant women or women who are breastfeeding * diabetes mellitus * celiac disease * coagulation disorders/anticoagulant therapy * not well functioning liver and gallbladder * active stomach or gut ulcer * biliary colic, calcified gallstones * acute infection of gallbladder or bile ducts, bile duct obstruction * intestinal disorders such as ulcerative colitis, Crohn's disease * lactose intolerance * allergies/sensitivity (asthma, allergic to bile acids, eczema, allergic rhinoconjunctivitis) * Intake of oral anticonception, barbiturates, antacid, colestyramine or colestipol, nitrendipine, cyclosporine, ciprofloxacine, rosuvastatine. * first degree relatives with celiac disease, Crohn's disease or type I diabetes mellitus Severe kidney malfunction