In addition to the five flavors that are the basic tastes of Chinese medicinal herbs, there are also astringent and bland flavors. TCM holds that astringent flavor falls under the sour flavor category and bland flavor falls under the sweet, so they are still included in the five flavors. The actions of astringent flavor are very similar to those of sour flavor, which all have astringent action. For example, Longgu (Os Draconis ) and Mull ( Concha Ostreae) can stop nocturnal emission, leucorrhea and profuse perspiration; Chishizhi ( Halloysitum Rubrum ) and Yuyuliang (Limonitum) can arrest diarrhea.
Those bland in flavor such as Zhuling (Polyporus) and Fuling (Poria) possess the actions of removing dampness and promoting diuresis, and are often used for edema and dysuria.
The nature and flavor are two kinds of medicinal properties that every Chinese herb possesses, and each of Chinese medicinal herbs must have the both properties. The natures and flavors deal with the pharmacological properties separately in different aspects. Only when you have a good understanding of the actions of both the natures and flavors, and combine them with each other, can you correctly understand their medicinal effects.
Those with same natures and flavors possess essential similar actions. Therefore, different natures and flavors of medicines result in their different actions. For instance, Huanglian (Rhizoma Coptidis) and Huangqin (Radix Scuteltariae) bitter in flavor and cold in nature, both can clear away heat and relieve toxic materials, purge fire and dry dampness; Huanglian (Rhizoma Coptidis) and Ganjiang (Rhizoma Zingiberis ), of which Huanglian ( Rhizoma Coptidis) is a kind of Chinese medicinal herbs bitter in flavor and cold in nature but Ganjiang (Rhizoma Zingiberis) is pungent in flavor and warm in nature are completely different in their actions. Ganjiang (Rhizoma Zingiberis) can expel cold, warm the middle energizer, restore yang, stop bleeding and warm the lung to resolve fluid retention, whose actions are completely different from those of Huanglian (Rhizoma Coptidis).
If the Chinese medicinal herbs are similar in nature but different in flavor; or similar in flavor but different in nature, their actions are both similar and different. For instance, both Huanglian (Rhizoma Coptidis ) and Shengdihuang ( Radix Rehmanniae) are cold in nature and both can clear away heat, but being bitter in flavor, Huanglian (Rhizoma Coptidis) possesses the action of drying dampness while Shengdihuang ( Radix Rehmanniae ), sweet in flavor, can promote the production of the body fluids. Therefore, Huanglian (Rhizoma Coptidis) can clear away heat and dry dampness and is indicated for damp-heat syndrome. Whereas, Shengdihuang (Radix Rehmanniae) can clear away heat and promote the production of the body fluids so it is indicated for consumption of the body fluids due to heat. Another example, both Shengjiang (Rhizoma Zingiberis Recens) and Bohe (Herba Menthae) are pungent in nature and possess dispersing action. But being warm in nature, Shengjiang ( Rhizoma Zingiberis Recens ) can eliminate cold while Bohe (Herba Menthae), cool in nature, can clear away heat.
Therefore, Shengjiang (Rhizoma Zingiberis Recens) is indicated for exterior syndrome due to wind-cold while Bohe (Herba Menthae) for exterior syndrome due to wind-heat. In a word, when the properties of Chinese medicinal herbs are distinguished, their natures and flavors cannot be separately considered.
