Ejiao began in Qin and Han dynasties and has a history of more than 2000 years. It is a traditional top tonic and blood tonic. It is made of donkey skin as the main raw material, and mixed with water of donkey skin glue (donkey skin glue, donkey glue is not boiled by donkey glue). Ejiao originated in Gudong County (now Gu 'ajing, Acheng Town, yanggu county). The best is amber, transparent and tasteless. Also called donkey hide glue. Ejiao, nourishing blood and nourishing yin, moistening dryness and stopping bleeding. Used for blood deficiency and chlorosis, dizziness, palpitation and restlessness, lung dryness and cough.
Ejiao comes from Dong 'e, called Ejiao, also called donkey skin Ejiao. Others include cowhide and deerskin Ejiao, later collectively referred to as Ejiao. The world's first pharmacopoeia, the fifteenth volume of Newly Revised Materia Medica promulgated by the Tang government, clearly records: "Ejiao is made from donkey skin and is called Ejiao. There are three kinds of calligraphy and painting, thin and clear. Thick and clear, it is called can-covering glue, which is used as medicine. Those who are turbid can use glue and cannot be used as medicine. " It is clearly pointed out in the literature that the raw material of Ejiao at that time was donkey skin.
"Zhou Li Kao Gong Ji Gong Ren" records: "Deer glue blue and white, horse glue red and white, cow glue red, mouse glue black, fish glue bait, rhinoceros glue yellow." Zheng Xuan's note: "It means cooking it with its skin or horns." As early as the Zhou Dynasty, rubber made of animal skins was carefully studied and classified, and cowhide was not the first choice of raw materials at that time, donkey skin and deerskin were more popular.