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 boiled cowhide and produced in East Asia, so it is named 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 was cowhide.