Five Flavours of Chinese Herbs
The five flavours of Chinese herbs or Wu Wei refer to the five different tastes: pungent (aromatic), sweet, sour, bitter and salty. They are related to the clinical actions of Chinese herbs and there is little difference bewteen the five flavours of Chinese herbs and the flavours normally perceived by the tongue.
The actions of Chinese medicinal herbs vary depending upon their associated flavour and the five flavours of Chinese herbs can be classified as follows.
Pungent flavoured medicinal herbs have the action of dispersing and promoting the circulation of Qi and Blood. They are generally indicated for use in treating exterior syndromes due to invasion of exogenous pathogenic factors and also for syndromes of Qi and Blood stagnation. For example, Zi Su Ye (Folium Perillae) and Bo He (Herba Mentha) can induce sweating to expel pathogenic factors from the exterior, Mu Xiang (Radix Aucklandiae) can circulate Qi, and Hong Hua (Flos Carthami) promotes blood circulation.
Sweet medicinal herbs have the actions of nourishing, harmonising and moistening. They are generally indicated for deficiency syndromes, disharmony between Spleen and Stomach, some pain syndromes, constipation due to Heat in the intestines and cough due to Lung-Heat etc. Huang Qi (Radix Astragali) and Shu Di Huang (Rhizoma Rehmanniae Preparata) are nourishing, Gan Cao (Radix Glycyrrhizae) can relieve spasms and pain, whilst Feng Mi (Honey) can moisten the intestine and promote purgation.
Chinese medicinal herbs with a sour flavour have absorbing, consolidating and astringent actions. They are commonly used to treat incessant sweating, chronic cough, chronic diarrhoea, spermatorrhoea, enuresis, prolonged metrorrhagia, metrostaxis and leukorrhoea caused by loss of essence due to qi deficiency. For example, Wu Mei (Fructus Mume) and Wu Wei Zi (Fructus Schisandrae) are used to relieve cough and diarrhoea, while Shan Zhu Yu (Fructus Corni) and Jin Ying Zi (Fructus Rosae Laevigatae) are used to relieve emission and enuresis.
Bitter flavoured herbs have the actions of drying or resolving dampness, purging and lowering. They have a wide range of uses and are frequently applied in the treatment of constipation due to fire-heat, dysphoria, cough due to rebellious Lung Qi, Damp-Heat or Cold-Damp syndrome. Some examples of bitter herbs are:
- Huang Lian (Rhizoma Coptidis) – Clears Heat and dries Dampness
- Cang Zhu (Rhizoma Atractylodis) – Dries Dampness
- Da Huang (Radix et Rhizoma Rhei) – Purges downwards
- Xing Ren (Semen Pruni Armeniacae) – Lowers and disperses Lung Qi
- Zhi Zi (Fructus Gardeniae) – Clears Heat and purges Fire
Medicinal herbs with a salty flavour have the action of softening hard nodules or masses, and promoting defecation and urination. As such they are othen used for scrofula, superficial nodules, abdominal masses and internal accumulation of dry stool. Hai Zao (Sargassum) and Kun Bu (Thallus Laminariae et Eckloniae) can soften hardness and disperse scrofula, while Mang Xiao (Natrii Sulfas) can relieve constipation through purgation.
In addition to the five flavours of Chinese herbs, there are also astringent and bland flavours. TCM theory places astringent flavours within the broader category of sour whilst bland herbs are grouped with sweet flavoured herbs. The actions of astringent and bland herbs are similar to those of sour and sweet respectively.
In conjunction with the four natures of Chinese herbs, an understanding of the five flavours of Chinese herbs provides practitioners with a complete understanding of their medicinal effects. It is important to understand that medicinal herbs with similar flavours can have different actions, for example Sheng Jiang (Rhizoma Zingiberis Recens) and Bo He (Herba Mentha) are both Pungent (Aromatic) in flavour and posses a dispersing action. However, Sheng Jiang is warm and can eliminate cold, while Bo He is cool in nature and thus can clear away heat.
The same is true for medicinal herbs with similar natures. Both Huang Lian (Rhizoma Coptidis) and Sheng Di Huang (Radix Rehmanniae) are cold in nature, however, Huang Lian is bitter so can dry dampness, whilst Sheng Di Huang is sweet and so can promote the production of body fluids.