It was believed that Emperor Tongzhi nearly cured his smallpox by taking ''guilinggao''. However, Empress Cixi believed his disease could be cured by worshipping a smallpox idol. She succeeded in convincing Tongzhi to quit his ''guilinggao'' regimen. As a result, the emperor died.
''Guilinggao'' is thought to be good for the skin, allowing for a healthier complexion upon repeated consumption. However this effect, if any, is most likely attributed to the additional herbal additives within the jelly.
Regular ''guilinggao'' jelly is black in appearance; however, the actual color is more of a dark brown. Naturally, it is not sweet, but slightly bitter, although sweeteners such as honey can be added to make it palatable.
Relatively inexpensive canned ''guilinggao'' jelly with pop tops and little plastic spoons can be found in Chinatowns in the United States and Canada. Although sweet and sometimes eaten as a dessert, it is very much an acquired taste.
''Guilinggao'' jelly is prepared from the powder form, very similar to how Jello is made. When it is prepared, other herbal substances, such as ginseng, are added to the jelly to give it certain tastes and medicinal values. The main ingredients of a typical Guilinggao jelly dessert found in North America contains: Water, sucrose, ''guilinggao'' powder, and American Ginseng.