Gastroparesis, or delayed gastric emptying, is a common cause of chronic nausea and vomiting as seen in a gastroenterology practice. Diabetic, postsurgical, and idiopathic causes remain the three most common forms of gastroparesis. In addition to nausea and vomiting, symptoms of gastroparesis may include early satiety, postprandial fullness, and abdominal pain. Physiologic changes that may explain symptoms in patients with gastroparesis, in addition to delayed gastric emptying, include impaired fundic accommodation, antral hypomotility, gastric dysrhythmias, pylorospasm, and perhaps visceral hypersensitivity. Diagnosis of gastroparesis is best determined using a radioisotope-labeled solid meal with scintigraphic imaging for at least 2 hours, and preferably 4 hours, postprandially. Most commonly, a 99mTc sulfur colloid-labeled egg sandwich with imaging at 0, 1, 2, and 4 hours is used. Extension of the gastric emptying test to 4 hours improves the accuracy of the test, but unfortunately, this is not commonly performed at many centers. Emptying of liquids remains normal until the late stages of gastroparesis and is less useful. The aims of treatment should be to control symptoms and maintain adequate nutrition and hydration. Patients should be advised to eat small meals and to limit their intake of fat and fiber. Additional dietary recommendations may include increasing caloric intake in the form of liquids. For diabetic patients, control of blood glucose levels is important, as symptom exacerbation is frequently associated with poor glycemic control. Specific treatment often begins with metoclopramide, 10 mg, up to four times daily, after a discussion of possible side effects with the patient. An antiemetic agent, such as prochlorperazine, 5 to 10 mg orally or 25 mg by suppository, can be added on an as-needed basis every 4 to 6 hours to control nausea. If these antiemetic medications are not effective, or if side effects develop, orally dissolving ondansetron, 8 mg every 8 to 12 hours, can be tried on an as-needed basis. If this regimen is unsuccessful, then alternative prokinetic agents--erythromycin, 125 mg, or tegaserod, 6 mg, prior to meals--can be tried. For cases refractory to these treatments, referral to a center with US Food and Drug Administration permission to use domperidone should be considered. Alternatively, symptom modulators such as low-dose tricyclic antidepressants can be tried to reduce symptoms, but these do not improve gastric emptying. In patients for whom all medical therapy fails, other options that are tried at experienced centers include the injection of botulinum toxin into the pylorus, placement of a feeding jejunostomy, and/or placement of a gastric electrical stimulator.