Eating half a watermelon diarrhea may be due to abdominal cold, infectious gastroenteritis, irritable bowel syndrome and other reasons. 1. Abdominal cold: patients eat half a watermelon if it is chilled, easy to lead to the patient’s abdomen is cold, will lead to gastrointestinal dysfunction, so that the gastrointestinal tract hyperperistalsis, leading to diarrhea symptoms. 2. Infectious gastroenteritis: patients consume watermelon if not clean, and patients consume more, will lead to pathogenic bacteria infection of the gastrointestinal tract, resulting in patients with diarrhea symptoms. 3. Irritable bowel syndrome: when the patient has irritable bowel syndrome, the patient’s gastrointestinal tract is more sensitive than others, and when stimulated by food and drink, it is easy to cause the patient to have diarrhea, abdominal pain and other symptoms. Patients ate half a watermelon diarrhea, in addition to the above reasons, there may also be other diseases, patients had better go to the hospital to check their own physical condition, if there is a gastrointestinal disease, please listen to the doctor’s advice timely treatment.