Inclusion Criteria:  Adult patients (18-75 years old). Men and women. Patients with gastroparesis.  Exclusion Criteria:  Patients will be excluded from the study if symptoms are thought to represent an organic disorder (e.g., peptic ulcer disease, hepatitis, pancreatitis, inflammatory bowel disease, a known malignancy, radiation-induced injury, an active infection, vasculitis, celiac disease), GERD, esophagitis, eosinophilic esophagitis or H. pylori. Patients with uncontrolled diabetes mellitus (hemoglobin A1C > 10). Patients with prior surgery to the esophagus, stomach or duodenum. Patients taking opioids, steroids, anti-histamines, immunosuppressive agents, NSAIDs, or mast cell stabilizing agents within the prior 3 months. Patients currently prescribed aspirin or aspirin regimens for other clinical reasons. Patients with known allergies to lactulose: mannitol will be excluded.