Watermelon, cold in nature and sweet in taste, has the effect of clearing heat and relieving summer heat, quenching thirst, diuretic and relieving annoyance, which helps to treat congestion in the chest and diaphragm, full of stuffiness, unhealthy urination, sores on the nose and mouth, summer heat, heat stroke, detoxification of alcohol, etc. It is called the “king of summer”. Watermelon flesh part of 94% is water, there are sugar, vitamins, a variety of amino acids and a small amount of inorganic salts, these substances can be most effective in the high temperature season to replenish the body’s water and nutrition needs; secondly, the water and inorganic salts ingested through metabolism into urine, but also take away excess heat, to achieve the role of summer heat and benefit. Who is not suitable to eat watermelon? Kidney insufficiency is not suitable to eat: patients with kidney insufficiency, the ability to excrete water from the body is reduced, often appearing lower limbs or whole body edema. If these patients eat too much watermelon, the intake of too much water and can not be discharged in a timely manner, resulting in excessive storage of water in the body, increased blood volume, which aggravates edema and induces acute heart failure. The initial phase of the cold should not eat: Chinese medicine believes that, whether it is wind-cold cold or wind-heat cold, the initial phase of the table, should be used to let the evil from the table and solve the dispersal treatment method. It is also believed that if you attack before the table is cleared, it will aggravate the disease, and watermelon has the effect of clearing heat, so eating watermelon at this time will aggravate the cold or prolong the course of the disease. Diabetic patients should not eat more: watermelon contains about 5% sugar, mainly grapevine, sucrose and some fructose, eating watermelon will cause blood sugar to rise. Normal people will secrete insulin in time to maintain blood sugar and urine sugar at normal levels, while diabetic patients are different, eating too much watermelon in a short period of time, not only the blood sugar is elevated, the more serious conditions may also lead to acidosis due to metabolic disorders. The patient with mouth ulcers should not eat: Chinese medicine believes that patients with mouth ulcers are mostly due to Yin deficiency, internal heat, false fire on the inflammation. Watermelon can be diuretic, if the mouth ulcer patients eat more watermelon, will make the mouth ulcer recovery water needed to be excessive discharge, thus aggravating the yin deficiency and internal heat, so that the ulcer is not easy to heal. Pregnant and maternal should not eat more: pregnant women are relatively insulin deficient, the stabilizing effect on blood sugar is reduced, the intake of watermelon will cause too much sugar in the blood concentration is too high, which is not good for health. In addition, pregnant and maternal physique is relatively weak, eating more cold watermelon will damage the spleen and stomach. Indigestion and gastrointestinal cold people should not eat: watermelon is a cold food, indigestion and gastrointestinal cold people eat more likely to damage the spleen and stomach, bloating, diarrhea, urination and other symptoms. Just after the exercise people should not eat: immediately after the exercise to eat watermelon, especially chilled watermelon, although it can replenish the lost water, but easy to produce stimulation of the digestive tract, damage to gastrointestinal health.