 Functional dyspepsia patients will be recruited and screened for inclusion in the study. The participants will be asked to not take proton pump inhibitors, drugs effecting gastric motility and NSAIDs and oral anticonception for fourteen weeks. First, they will stop with their daily drug intake of PPIs and NSAIDs for two weeks, then they will take placebo or UDC for four weeks, two doses every day during lunch and dinner. Afterwards, there will be a washout period of four weeks, and again four weeks of UDC or placebo intake. The patients will receive a diary in which they describe their symptomsdiscomforts every day for 14 weeks. All participants and the investigator will be blinded to the nature UDC or placebo of the pills. The random order in which a certain patient gets his pills has been decided by the pharmacy of UZ Leuven and is also unknown for the investigator double blinded. During week two, four, six, eight, ten and twelve we will have a phone conversation with the patients to discuss their symptomsdiscomforts. 