Eating leeks upset stomach is mainly considered to be caused by improper diet and digestive system diseases and other factors. 1. Improper diet: leek itself belongs to the stimulating, difficult to digest food, such as one-time consumption of too much, can cause stimulation of the gastric mucosa, aggravate the burden on the gastrointestinal tract, and then the symptoms of gastric discomfort. 2. Digestive system diseases: patients with gastritis, gastric ulcer, duodenal ulcer and other digestive system diseases, after eating leeks and other stimulating food, can lead to excessive secretion of gastric acid, gastrointestinal peristalsis, the original aggravation of the condition, an acute attack, which causes gastric discomfort symptoms. If the patient’s symptoms persist or are severe, he should seek medical attention as soon as possible and intervene under the guidance of a professional doctor to avoid delaying his condition.