'Four properties and five flavours' of Chinese herbs

The range of herbs used in Traditional Chinese Medicine can generally be categorised into ‘four properties and five flavours’. Each herb can be identified to have a certain property and flavour.

‘Properties’ refer to the nature of a herb as being cold, hot, cool or warm. These properties are sorted out as so based on their therapeutic effect on the human body: for example, herbs which treat excess heat (hyperactivity of yang) have a cool or cold property, while those which treat excess cold (yin) have a warm or hot property. Warm and hot natured herbs are of opposite property to cool and cold ones; cool and cold natured herbs only differ in degree, as with warm and hot herbs.

‘Flavours’ refer to the taste of the herb as being sour, bitter, sweet, pungent, and salty. Herbs of similar taste are generally also of similar composition and effect, while those of different taste are generally also of different composition and effect. The ‘flavour’ assigned to a herb does not only describe its actual taste – the ‘flavours’ are sorted out by the characteristics of the herbs and their therapeutic effects. The five flavours and their associated characteristics are as follows:

• Sour herbs induce astringency and arrest discharge, and are often used to treat condition such as sweating due to debility, chronic cough, chronic diarrhea, emission, etc.
• Bitter herbs have the effect of clearing heat, purging fire, sending down the adverse flow of qi to treat cough and vomiting, relaxing the bowels, eliminating dampness etc. Such herbs are used mostly for illnesses of pathogenic fire, cough with yellow phlegm, vomiting, constipation due to excess heat, etc.
• Sweet herbs have the effect of nourishing, replenishing, tonifying or enriching the different parts or organs of the body, normalising the function of the stomach and spleen, harmonising the properties of different herbs, and relieving spasm and pain. Herbs of sweet flavour are generally effective in treating illnesses associated with deficiency, dry cough, constipation due to deficiency of qi, blood, yin or yang, incoordination between the spleen and stomach, as well as various pains. Some sweet herbs also have the effect of detoxification.
• Pungent herbs are used to disperse seasonal pathogens from the body and promoting the circulation of Qi and blood. They are usually used for the treatment of superficial and mild illnesses.
• Salty herbs have the effect of purging, softening and resolving hard mass. They are used in relieving constipation by purgation, treating dry stool and constipation, scrofula, goiter, mass in the abdomen, and other conditions.