Gastroparesis is a disorder in which the stomach takes too long to empty its contents. The most common known cause of gastroparesis is diabetes. At least 20 percent of people with type I diabetes develop gastroparesis. It can also occur in people with type 2 diabetes, although less often.
Other causes of gastroparesis include infections, complications from stomach or ulcer surgery, endocrine disorders, certain medications, cancer, radiation treatments, immune diseases like lupus or scleroderma, and other muscular and neurological disorders in the body.
Gastroparesis happens when nerves to the stomach are damaged or stop working. The vagus nerve controls the movement of food through the digestive tract. If the vagus nerve is damaged, the muscles of the stomach and intestines do not work normally, and the movement of food is slowed or stopped.

