Donkey-hide gelatin or ass-hide glue (Latin: colla corii asini) is gelatin obtained from the skin of the donkey (Equus asinus) by soaking and stewing. It is used as an ingredient in the traditional medicine of China, where it is called ejiao (simplified Chinese: 阿胶; traditional Chinese: 阿膠; pinyin: ē jiāo).
The gelatin is produced in several coastal provinces of China: Jiangsu, Zhejiang, Shandong. Shandong’s Dong’e County was where “ejiao” got its name.
According to a ca. 1723 account by the French Jesuit Dominique Parrenin, there was a well in Dong’e which was normally kept closed and sealed, and which was only opened when water was taken to be used in preparation of ejiao for the emperor’s court.
Donkey Hide Manufacture
According to Parennin, the product was traditionally prepared during the late fall and winter (from after the harvest and until the beginning of March). It was supposed to be made from the skin of a recently killed well-nourished black donkey. Since the supply of this material was rather limited, it was said that a large amount of “fake” ejiao was also manufactured, using skins from mules, horses, camels, pigs, and sometimes, it was said, even from old shoes; a bit of “real stuff” was added to it, to deceive consumers.
Ejiao is either prepared as dry gelatin or mixed with powdered oyster shell or pollen to form glue balls. It tastes sweet.
Jesuits noted that while the “real” ejiao has no disagreeable taste or smell, the fake product could be distinguished by its unpleasant smell and taste, even when it was made from pig skins (which, supposedly, provided the best approximation of the real thing).
In the 21st century, ejiao manufacturers experience problems with the supply of genuine donkey hides, as fewer people raise these animals these days. The decreasing supply combined with strong demand for ejiao has led to greatly increased prices for donkey hides in China. This trend is also supported by restrictions on importing animal hides from outside the country. Qin Yufeng, the chairman of a major ejiao manufacturer and a member of Shandong’s provincial legislature, has advocated for government support for donkey husbandry.
