What did people think caused disease and illness during Tang Dynasty China and how did they treat them?
Ideas about health and illness entered Tang Dynasty China (618-907 CE) from many sources: India, Iran, Japan, Southeast Asia and the horse nomads of Inner Asia also made contributions. Yet Chinese sages and doctors of the period nearly always responded by seeking the scientific principles underlying the new ideas and seeking how to understand diseases and, hence, remove them (some malevolent people of course wished to inflict illnesses on people for their own purposes). While some scientists of the modern age would not recognize the validity of Tang Dynasty scientific methods, they were at least mostly systematic and aimed to integrate diverse observed phenomena into comprehensible conceptual frameworks. For example, if demons were understood to be responsible for bringing about a particular disease, then it would be logical to identify and determine means of discomforting those demons.
In general, physicians and people in general believed that disease or illness could be caused by one or more of a variety of different causes. They include natural and supernatural causes – the latter included gods, demons, magic and ghosts. Natural causes could be internal (something goes wrong with the body) or external (someone strikes the body with a weapon) or neither but resulting from overindulgence in drink, food or carnal appetites. A doctor, whether one peddling oriental medicine, acupuncture or therapeutic massage or a Taoist priest armed with sacred texts to control ghosts and demons, would begin by trying to diagnose the disease correctly. Some were able to do this more efficiently than others, of course, just as doctors today vary in their abilities. Generally, doctors schooled in one form of thought or another tended to diagnose illnesses based on their existing thought patterns. Taoist priests, for example, tended to see the influence of demons and ghosts everywhere; herbalists, on the other hand, tended to see opportunities for herbal tinctures and infusions and so forth wherever they looked. Inevitably, it took a few visits from different doctors to find a suitable treatment, by which time the patient had either recovered despite the best or worst efforts of doctors or had died. In the past, most doctors did good as a result of unintended consequences, in those cases when they were not able to follow tried and tested methods. Usually, although not always, women such as midwives had better and simpler ideas about what would and would not work in particular, regularly occurring situations.
In any case, it was probably better to avoid those many doctors who had a strong but unjustified belief in the blood-letting capabilities of the so-called nine vermin; nine worms, of various types, which were introduced into the body of the victim/patients.
For more details, see Charles Benn’s China s Golden Age: Everyday Life in the Tang Dynasty.