Onion (scientific name: Allium cepa), alias ball onion, round onion, jade onion, onion, Dutch onion, skin teeth, etc., Lily family, genus Allium, biennial herbaceous plants. Onion contains prostaglandin A, which can reduce peripheral vascular resistance and blood viscosity, and can be used to lower blood pressure, refresh the mind, relieve stress and prevent colds. In addition, onions can also remove oxygen free radicals in the body, enhance metabolism, anti-aging, prevention of osteoporosis, is suitable for middle-aged and elderly health food.