Four properties of Chinese medicinal herbs, cold, hot, warm and cool, are also called the four natures or four xing in TCM. Cold-cool and warm-hot are two completely different categories of natures, cold-cool belonging to yin, and warm-hot to yang, whereas cold and cool or hot and warm are only different, to some degrees, in their variance. Chinese medicinal herbs with cold-cool nature can clear away heat, purge fire and eliminate toxic materials, which are mainly used for heat-syndrome; Chinese medicinal herbs with warm-hot nature have the actions of expelling cold and restoring yang, which are mainly used for cold-syndrome.

The five flavors of Chinese medicinal herbs refer to the five different tastes, pungent, sweet, sour, bitter and salty, which can be tasted by the tongue. With the development of the theory dealing with the medicinal properties, some flavors are summarized out of clinical actions of Chinese medicinal herbs; therefore, there is a little difference between the flavors of medicinal herbs and the tastes got by tongue. The Chinese medicinal herbs with same flavor mostly possess similar actions while the medicinal herbs with different flavors show different actions in the treatment, which are shown as follows.