Watermelon can clear the heat and relieve the summer heat, but cold, long-term consumption of large amounts of watermelon may cause diarrhea, abdominal pain, bloating, indigestion and other symptoms, especially chilled watermelon, so poor gastrointestinal function and weak spleen and stomach, pregnant women should be careful to eat. In addition, there are effects such as elevated blood sugar and increased kidney burden.1. Elevated blood sugar: The main sugar in watermelon is glucose and fructose, which are easily absorbed by the body, and a large intake of normal healthy people will have a transient increase in blood sugar. And for diabetic patients, because the body can not secrete insulin in time to maintain blood sugar balance, so too much watermelon eating will obviously cause blood sugar elevation. Diabetic patients should eat watermelon in limited quantities, and it is recommended that they eat it between meals if their blood sugar is stable, not more than 250 grams each time, and they should monitor their blood sugar at all times; 2, increase the burden on the kidneys: because watermelon contains a lot of water, it dilutes the blood and causes a decrease in the secretion of anti-diuretic hormone, which has less effect on normal people. However, for patients with renal insufficiency, the lower limb edema and even general edema caused by the inability to drain normally, eating too much watermelon at this time will increase the burden on the kidneys and even induce acute heart failure; 3, other adverse reactions: for patients with wind-cold colds, mouth ulcers and other diseases, eating large amounts of watermelon can aggravate the condition. In addition, it is not recommended that patients ingest watermelon that has been placed for too long to prevent bacterial growth causing gastrointestinal infection or inflammation.