The nutritional value of raw onions is different from that of cooked onions. \x0d\ If cooked, the nutrition will be greatly reduced. It is recommended to eat raw. You should not eat it on an empty stomach. You can eat it with lunch or dinner. Don't eat too much at a time. \x0d\ Onion, also known as onion, is closely related to garlic and has similar spicy taste and chemical structure. Onion contains almost no fat, but its essential oil contains a mixture, which contains sulfide, which can lower cholesterol. It is reported that onion is the only known plant containing prostaglandin, and it also contains components that can activate fibrinolytic protein activity. These substances are strong vasodilators, which can reduce the resistance of peripheral blood vessels and coronary arteries, resist the effect of pressor substances such as catecholamine in human body, promote the excretion of sodium salts, and thus lower blood pressure. It can be said that onion is a good plant medicine for patients with cardiovascular diseases such as hyperlipidemia and hypertension. So onions have been valued since ancient times. \x0d\\x0d\ Every 100g of fresh onion contains about C8mg of water, 1. 1g of protein, 8. 1g of carbohydrate, 0.9g of crude fiber, 0.2g of fat, 0.5g of ash, 0.02mg of carotene and b/kloc-0. Some bioactive components in onion can promote the excretion of sodium water in kidney and have diuretic effect; Onion oil can lower blood fat; Onion has a high K factor (K-Na ratio) (33.42) and contains prostaglandin A 1, which can relax blood vessels, reduce the resistance of peripheral blood vessels and coronary vessels, and resist catecholamine substances, thus showing the effect of lowering blood pressure. Methylsulfonylurea contained in onion has the function of lowering blood sugar; Onions contain high selenium content and have anti-cancer effect. In recent years, medical clinic and research have proved that onion has a variety of high physiological and medicinal values. It is regarded as a multifunctional nutritional health food with blood lipid lowering, blood pressure lowering and anti-cancer in nutritious diet, and enjoys the reputation of "the queen of vegetables".