Gastroparesis Registry 4

Inclusion Criteria: * Age at least 18 years at initial screening visit * Symptoms of Gp and/or FD of at least 12-weeks duration with varying degrees of nausea, vomiting, early satiety, postprandial fullness, abdominal pain, abdominal burning. Thus, patients can enter the GpR4 registry primarily with abdominal pain suggesting FD-Epigastric Pain Syndrome. * Successful completion of gastric emptying scintigraphy of solids using the 4-hour Egg Beaters® protocol (or equivalent generic liquid egg white meal) within the last 9 months * Negative upper endoscopy or upper radiographic GI series within 5 years of registration Exclusion Criteria: * Use of narcotic analgesics greater than three days per week * Presence of other conditions that could explain the patient's symptoms such as: * Pyloric or intestinal obstruction as evidenced by EGD, UGI, or Abdominal CT * Active inflammatory bowel disease * Known eosinophilic gastroenteritis or eosinophilic esophagitis * Primary neurological conditions that can cause nausea and vomiting such as increased intracranial pressure, space occupying or inflammatory/infectious lesions * Acute or chronic renal failure (serum creatinine \>3 mg/dL) and/or on hemodialysis or peritoneal dialysis * Acute liver failure or advanced liver disease (Child's B or C; a Child-Pugh-Turcotte (CPT) score of ≥7) * Pancreatic disorder if present on pancreatic imaging or pancreatic function testing * Prior gastric surgery including total or subtotal (near complete) gastric resection, esophagectomy, gastrojejunostomy, gastric bypass, gastric sleeve, pyloroplasty, pyloromyotomy, or any fundoplication (Nissen, Tor) * Any other condition, which in the opinion of the investigator, could explain the symptoms or interfere with study requirements * Females who are pregnant. A urine pregnancy test is routinely obtained on all females immediately prior to gastric emptying procedures. * Inability to comply with or complete the gastric emptying scintigraphy test (including allergy to eggs) * Inability to obtain informed consent