 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.