A lot! Maturity time varies from place to place. It went on the market in May, and now the greenhouse technology can eat watermelon all year round. Fruit juice contains almost all kinds of nutrients needed by human body except fat, such as vitamins A, B, C and protein, glucose, sucrose, fructose, malic acid, glutamic acid, citrulline, arginine, phosphoric acid, calcium, iron, phosphorus and crude fiber. Watermelon tastes sweet and cold, and has the effects of clearing away heat and relieving vexation, quenching thirst and relieving summer heat, soothing the middle energizer, treating laryngitis, diuresis, treating bloody dysentery and hangover. Suitable for heatstroke, fever, excess heat, body fluid injury, polydipsia, short and reddish urine, sore throat, etc. When acute fever, fever, thirst, hyperhidrosis and irritability occur, drinking fresh watermelon juice can clear away heat and quench thirst. Watermelon peel is used as medicine fresh or dry. Sweet and cool, it has the effects of clearing heat, diuresis and detumescence. Can be used for treating dysuria, edema and damp-heat jaundice. Watermelon Cui Yi, the green part of watermelon peel, can treat diseases such as edema, scald and nephritis. Using its decoction instead of tea is also a good cool drink to relieve summer heat. Modern pharmacological research believes that sugar, salt and protease contained in watermelon can treat nephritis and lower blood pressure. Watermelon kernels also contain an ingredient that can lower blood pressure. Eating raw or fried food 9- 15g can lower blood pressure and relieve the symptoms of acute cystitis. The decoction of watermelon root, stem and leaf is taken orally, which has certain curative effect on diarrhea and enteritis. Watermelon peel contains glucose, amino acids, malic acid, lycopene and C. After the watermelon peel is dried in the sun, it can relieve summer heat, diminish inflammation, lower blood pressure and reduce the deposition of cholesterol on the arterial wall. When eating watermelon, there are also some problems that need attention. First, don't eat too much, otherwise it will hurt the spleen and stomach and cause pharyngitis. Watermelon is a cold product, and eating too much is easy to hurt the spleen and stomach. Therefore, people with spleen and stomach deficiency and cold, dyspepsia and loose stool should eat less, while eating more will lead to abdominal distension, diarrhea, loss of appetite, accumulation of cold and dampness, and cause diseases. Eating too much watermelon at a time will dilute gastric juice, cause indigestion and decrease gastrointestinal resistance. Second, don't eat watermelon at the beginning of a cold, otherwise it will aggravate the cold or prolong the cure time. Whether wind-cold cold or wind-heat cold belongs to exterior syndrome at the initial stage, it should be treated by divergent methods to solve the disease from the exterior. Traditional Chinese medicine believes that exterior and interior are not attacked, otherwise exterior evil will enter the interior, and the condition will be aggravated. In the early stage of a cold, eating watermelon is equivalent to eating drugs that clear away heat from the interior surface, which will lead to the entry of pathogenic factors, aggravate the cold or prolong the cure time. However, when the cold gets worse and there are fever symptoms such as high fever, thirst, sore throat and yellow urine, you can eat some watermelons while taking normal drugs, which is helpful for the recovery of the cold. Third, don't eat watermelons that have been open for too long. When the temperature is high, watermelon is easy to deteriorate after being opened for a long time, which will breed germs and lead to intestinal infectious diseases. Therefore, when eating watermelon, we should pay attention to choosing ripe fresh watermelon. Fourth, people with renal insufficiency should not eat it. Eating a lot of watermelon in a short period of time will increase the water in the body, which exceeds the physiological capacity of the human body. In patients with renal insufficiency, the ability of kidney to regulate water is greatly reduced, and too much water entering the body can not be regulated and excreted, resulting in a sharp increase in blood volume and easy death due to acute heart failure. Fifth, people with oral ulcers should not eat. Traditional Chinese medicine believes that the main causes of oral ulcers are internal heat due to yin deficiency, disturbance of virtual fire and burning of flesh and blood veins. Watermelon has diuretic effect. If people with oral ulcer eat more watermelon, the water normally needed in the body will be discharged through the diuretic effect of watermelon, which will aggravate the state of insufficient vaginal fluid. Yin deficiency will increase internal heat and aggravate oral ulcer. Sixth, diabetics should eat less. The sugar content of watermelon is about 5%. If diabetics eat too much watermelon, it will also lead to high blood sugar, increased urine sugar and other consequences, and even severe ketoacidosis coma. If you eat 25-50 grams of watermelon at a time, it will have little effect on diabetics, so diabetics should pay attention to the right amount of watermelon.