Walnuts are native to the Eurasian region between the Balkans and southwestern China. They are distributed in North China, Northwest China and South China. They are generally born on slopes and hills at an altitude of 400-1800 meters. Walnut kernels have high oil content and can be eaten raw or pressed with oil. The wood is solid and is also a good hardwood material. [2] Walnut is also one of the four major nuts in the world. Walnut efficacy value is rich, according to the "Chongqing Herbal Medicine" recorded walnut root: "Insecticide, attack poison. Treatment of old toothache, and can replenish qi." Walnut species can warm and tonify the lungs and kidneys, moisten the intestines and defecate, and is used for kidney deficiency and tinnitus. Walnut root can kill insects and attack poison.