RecruitingPhase 2Drug trialEffects of Ondansetron on Gastrointestinal Sensorimotor Dysfunctions in Diabetes Mellitus and DyspepsiaResearchers are trying to understand why people with indigestion and diabetes mellitus have gastrointestinal symptoms and in particular to understand whether symptoms are related to increased sensitivity to nutrients in the small intestine. As part of this investigation, a medication called ondansetron will also be studied to determine its effects on gastrointestinal function and associated symptoms.