Glossary

Hu huo bing is described by Zhang Zhong-Jing in Essentials from the Golden Cabinet as:

"Hu Huo disease manifests like Cold Damage with reticence, a desire to sleep, inability to close the eyes, and fidgetiness whether lying down or upright. Erosion of the throat indicated Huo disease, and erosion of the anal and genital orifices indicates Hu disease. Other signs include no desire to drink or eat, aversion to the smell of food, and a facial complexion that alternates between red, black and white. Erosion of the upper manifests with a hoarse voice. Gan Cao Xie Xin Tang (Licorice Decoction to Drain the Heart) is indicated" (trans. Sung, 2008, Understanding the Jin Gue Yao Lüe).

Most authors consider it to be an early description of Behçet's disease, a rare autoimmune disorder but this does not explain the unusual name. Fruehauf translates 惑 as vermin while most other sources use "Confusion" or "Puzzlement". Although he does not explain this translation he does discuss the notion of foxes being seen as promiscuous shape shifting spirit animals implying that the name may be referring to sexually transmitted diseases such as syphilis¹ or simultaneous oral and genital herpes believed to be contracted as a result of being enchanted and seduced by a fox spirit

The recipe for Gan Cao Xie Xin Tang (Licorice Decoction to Drain the Heart) uses fresh licorice to resolve toxicity instead of the honey fried variety mentioned earlier in the Shang Han Lun.

Another formula recommended by Zhang Zhong-Jing when there is pus formation and no Exterior signs is Chi Dou Dang Gui San (Adzuki Bean and Angelica Powder).

For more information about fox spirits I would recommend the following books:

Fruehauf (2010): Gan Cao Xie Xin Tang: pinellia[sic] purge the heart decoction - A Forgotten Key Remedy for the Treatment of Toxic Skin Conditions. Classicalchinesemedicine.org.

Kang Xiaofei (2006). The Cult of the Fox: Power, Gender and Popular Religion in Late Imperial and Modern China. Columbia University Press.

Pu Songling (1740). Strange Tales from a Chinese Studio (聊齋誌異, Liaozhai Zhiyi). Trans. Milford, J. 2006. Penguin Classics.

¹Syphilis is called Mei Du, 梅毒, Plum Poison, in Chinese medicine and the first recorded case was in Europe over a millenium later, believed to have come from the New World, not Asia.