This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Gastroparesis, or delayed gastric emptying, is a disorder where the food does not move or moves very slowly from the stomach to the small intestine. In gastroparesis, the muscles of the stomach do not work well and digestion takes an abnormally long time. Symptoms of gastroparesis include bloating, nausea, vomiting, weight loss due to poor absorption of nutrients, early fullness while eating meals, heartburn, and abdominal pain. Complications can occur including dehydration, electrolyte abnormalities, blood sugar abnormalities, malnutrition, vitamin deficiencies, stomach ulcers, gastroesophageal reflux, esophagitis, small bowel bacterial overgrowth, and metabolic bone disease. In rare cases, food that is poorly digested can collect in the stomach and form a bezoar, a mass of undigested material that can cause a blockage in the gastrointestinal tract. Gastroparesis is more common in people with diabetes and those who have had recent stomach or intestinal surgery. Other causes include infections, hormonal disorders like hypothyroidism, connective tissue disorders like scleroderma, autoimmune conditions, neuromuscular diseases, psychological conditions, and eating disorders. In some cases, the cause is not known (idiopathic). Diagnosis is made on the basis of a radiographic gastric emptying test.
Treatment may include dietary modifications such as adjusting the timing and size of meals, consuming more liquid-based meals, or avoiding foods that are more difficult to digest (such as fatty foods, or foods with too much fiber). Other treatments may include endoscopic procedures to break the bezoar apart and remove it, feeding tubes, surgery, placement of an electrical stimulator, and medication such as metoclopramide, domperidone, erythromycin and cisapride. With proper management many people with gastroparesis can live a relatively normal life. However, others may not tolerate treatment and may experience significant complications, a decreased quality of life, and reduced survival. 
For more information, visit GARD.