Tastes and Herb Properties according to TCM
To use herbs within the scope of Chinese Herbology, one must first understand the properties (the personality which dictates how an herb will function) of each herb beyond the scope of its category. Properties are tastes, temperatures, and qualities of an herb. The possible tastes are sweet, sour, bitter, pungent, bland, salty, astringent, and aromatic. It may have other qualities such as toxic. The possible temperatures are cool, cold, warm, neutral, and hot.
It is very important to understand that herbs do not possess one quality. They are most always a combination of properties and temperatures and may reach one to as many as twelve organ systems. These combinations of qualities give each herb their character, and if you understand the functions behind the properties, than you can surmise what an herb is capable of before even becoming acquainted with it. Learning to combine the appropriate formula for each patient is a medical art which takes years to develop. A tremendous amount of respect should be given to those who do it well.
Sweet: If an herb is sweet, it can do one of a few things. This depends on it category and the other tastes and qualities it is combined with. For example, an herb which is sweet and cold and falls within the yin tonic category will tonify yin. These herbs are usually sticky and can not be mistaken for much else. However, an herb which is sweet and cold can also promote urination. These herbs are found within different categories. It is a quality an herb may possess in addition to its category. Another function of herbs which are sweet and cold is promoting fluids. This is a common function of herbs in the quell fire category where water is needed to put out the fire. Warm herbs which are sweet are found in the tonify Yang category. This is another example of sweetness which is tonifying in nature. The Qi tonics share these properties with the exception of a few neutral temperatured herbs. The digestive category is also filled with sweet herbs because most of these herbs have other functions which are moving (digestive) in nature and the sweetness helps to strengthen (tonify) as the other properties function to digest. A good herbalist understands that sweetness tends to be sticky, and therefore, will clog things up if they are not moving well. To prevent this kind of clogging, these herbs must be combined with herbs which are moving in nature to protect against this side effect.
Bitter: This quality functions to descend, to dry, to detoxify. Many herbs in the pharmacopoeia are bitter. This taste is one which spans numerous categories. If one looks closer at each individual herb, if it contains a bitter quality, it will serve one of the above functions. It is important to note that because this taste has a drying quality to it, It is prudent to protect against it in preexisting conditions of dryness, such as yin deficiency. Because bitterness descends, it is also prudent to beware of this quality in pregnant women as the fetus could be encouraged to descend as well with the use of such herbs.
Pungent: This is a moving force used for such things as moving Qi, ridding the body of phlegm, or expelling pathogens from the surface of the body outward. It is often seen in the anti-rheumatic category (also known as the Wind-Damp category) to eradicate painful joint conditions which Oriental Medicine recognizes as a Wind-Damp pathogen lodged in the interior. This is because an herb which is pungent in nature possesses the power of movement. It is present in numerous other categories where movement is a function of the category. One must be careful in those who are weak, or dry, or even pregnant in using such herbs. It is also important to remember that movement, like us when we exercise, creates warmth. So if you use an herb which is pungent and cold in nature, don't be surprised if some warmth results despite the cold temperature of the herb.
Salty: A salty herbs has the ability to detoxify (sore throat for example), dissolve (nodules, for example), and carry herbs to the Kidney system. Most herbs which from animal products or sea products are salty. If they are from the sea, they are almost always salty and cold. Salt, as we all know may encourage the retention of fluids in the body, so other herbs must be used to guard against this tendency so as not to disrupt the fluid balance of the patient.
Bland: Bland herbs are mostly only seen in the drain damp category. This group is made up of sweet and cold herbs (which we stated previously promotes urination) and sweet and bland herbs which accomplish the same task. Bland herbs are said to be mild and without taste, hence their name.
Astringent and Sour: Sour is very similar to astringent in its function and many herbs which are astringent are sour, and all herbs which are sour have some sort of astringent function. Let us clarify this issue. There is an entire category of astringent herbs some of which are sour and there are many sour herbs which astringe slightly, but not strongly enough to be primarily categorized as an astringent. Sour herbs "gently preserve" (hence the expression preserving Yin) while astringents actually "restrain" (as in urine, sweat, semen, etc...)! Bai Shao (Peoniae Albae), for example, is sour. It is definitely not an astringent herb, yet it does gently astringe the blood it is used to supply. Its primary function is to nourish blood and this is its primary category. Its secondary functions are based on the fact that it is sour.
Hot: In the Chinese pharmacopoeia, there is one basic group of hot herbs. This is the interior warming category. These herbs are used for conditions of severe and often acute internal coldness. There is only one exception to this rule. There is one Yang tonic which is hot. Hot is obviously warming and moving as well. Unlike cold which contracts, heat expands.
Warm: This temperature will create movement and of course warmth. It is important not to use warm herbs with patients with warm conditions unless the formula is very well balanced as not to exacerbate the hot condition. Warm herbs are also drying in nature and may dry up the Yin if not combined properly with the appropriate herbs in such circumstances.
Cold: Coldness does inside the body exactly what it does to us when we are exposed to it outside. It contracts! It slows down and contracts. This is not a temperature you want to use if stagnation is a problem, unless of course, you are combining the cold herbs with other herbs that move so as to prevent against this side effect.
Neutral: There are not too many neutral herbs in the pharmacopoeia These herbs are said to be neither hot nor cold and are often considered more gentle because of this.
Aromatic: Aromatic is drying, transforming, and moves upward and outward. Many of the herbs which are used to release exterior syndromes (as with the common cold) are assisted by the aromatic quality which assists their already pungent nature in releasing the pathogenic invasion from the body. Other herbs which are aromatic are herbs used to transform dampness. These herbs are focused on treating damp conditions and transforming (drying and moving it) this dampness. The aromatic quality, as I said, is ascending in nature which assists in the "awakening" of the Spleen which in turn will naturally rid the body of its damp condition.