Douchi is a traditional food in China, similar to bean paste, and it is an indispensable condiment in people's daily life. It can not only cook vegetables and braised fish, but also stir-fry or steam food alone, and can also cook juice instead of soy sauce. Douchi is made of black beans or soybeans, which are washed, boiled and cooled, fermented in a pot, pickled and finally dried in the sun. There are two kinds according to whether salt is added or not. At first, people called Douchi "Fu You" because in ancient times, soybeans were called "Fu You", which meant that soybeans were claustrophobic when cooked. In the Qin Dynasty, people renamed it "Douchi", and this name has been used ever since. Douchi is popular because it is not only delicious, but also nutritious, containing a lot of protein, fat, calcium, phosphorus, iron, cobalt, selenium, molybdenum, vitamin B 1, vitamin B2, nicotinic acid and so on. Studies have confirmed that the cobalt content in douchi is 40 times that of wheat, which has a good effect on preventing coronary heart disease; The content of molybdenum is 50 times that of wheat, and the content of selenium is higher than that of garlic and onion with high selenium. Both molybdenum and selenium have strong anticancer effects. Douchi also contains a lot of urinary hormones that can dissolve thrombus, which can effectively prevent the formation of cerebral thrombosis and is very effective in improving cerebral blood flow and preventing and treating Alzheimer's Harmo's disease. In traditional Chinese medicine, fermented soybean is often used to treat phlegm, chest tightness, vomiting, indigestion, memory loss and drunkenness. Li Shizhen's Compendium of Materia Medica said: "Black beans are flat in nature and warm when fermented, so they can rise and fall. Sweat when you get onions, vomit when you get salt, cure the wind when you get wine, stop bleeding when you get garlic, and stop sweating when you fry, which also helps to stop sweating. " According to modern medicine, fermented soybean has the effects of relieving exterior syndrome, clearing away heat, penetrating rash and detoxicating, and is suitable for wind-heat headache, chest tightness, vomiting and excessive phlegm.