• Provision of signed and dated informed consent form.

• Stated willingness to comply with all study procedures and availability for the duration of the study.

• Male or female, aged 18-85

• Symptoms of gastroparesis, either diabetic or idiopathic etiology

• Symptoms of gastroparesis with minimum Gastroparesis Cardinal Symptom Index (GCSI) score of 2.0 (18/45 x 5)

• Individual will have had a prior 4-hour gastric emptying scintigraphy test performed for clinical evaluation within the last 6 months. This gastric emptying test would be done for clinical evaluation and is not part of the research study. From these participants with gastroparesis symptoms, we will include those with delayed gastric emptying as well as those with normal gastric emptying.

• Participant must not initiate any new treatments until completion of the study procedures.

• Willingness to:

‣ Stop histamine 2 antagonists, prokinetics (e.g., metoclopramide, erythromycin, domperidone, prucalopride), narcotics, anticholinergics, constipation medications (over the counter laxatives, isotonic polyethylene glycol (PEG) electrolyte preparations (e.g. MiraLax), prescription laxatives (e.g. lubiprostone), proton pump inhibitors, cannabinoids, and cannabidiol (CBD) for 3 days prior to each visit;

⁃ Abstain from food and water after midnight (at least for 8 hours) before the start of each visit until after the visit.

• Provision of signed and dated informed consent form

• Male or female, aged 18 or older

• Undergoing an upper endoscopy for their clinical evaluation of diarrhea, GI bleed, or iron-deficiency anemia, or evaluation for bariatric surgery.

• Do not have upper GI symptoms greater than 1 as assessed by the Gastroparesis Cardinal Symptom Index (GCSI) of PAGI-SYM questionnaire.