After eating grapes stomach pain, there may be the following reasons: 1, the patient itself has chronic gastritis, gastric ulcer, duodenitis, duodenal ulcer and other diseases of the stomach and duodenum, because after eating grapes, grapes are relatively sweet, easy to stimulate the stomach or duodenal ulcer surface. 2, if the grapes are not washed, after eating easily cause acute gastroenteritis performance, some accompanied by diarrhea, fever and other symptoms. If the symptoms are not obvious, you can drink the appropriate water to observe, if the symptoms are obvious, you need to go to the hospital in a timely manner.