Basic Principles

Herbs and Their Yin and Yang Properties

In traditional Chinese medicine (TCM), physicians stress on the overall balance of patients, the remedies are designed to work on the whole body instead of specific systems. With this holistic approach, physicians always pay attention to the general properties of herbs such as the "natures", "flavors" and "movements," so as to help them prescribe remedies that match the therapeutic nature with diagnosed disharmony patterns. The yin and yang theory are used in categorized the herbal properties and as a basic guideline in herbal applications. Generally, cold and cool nature herbs belong to yin, while hot and warm herbs belong to yang. Yin herbs have flavors like sour, bitter and salty, while yang herbs have flavors like sweet and pungent. Herbs with floating or ascending quality are part of yang, while herbs with sinking or descending quality are part of yin.

Herb Properties	Yin Category	Yang Category
The four natures and associated therapeutic actions	Cold and cool: clear heat, purge fire and detoxify.	Hot and warm: warm up the internal body, expel coldness and promote physiological functions.
The five flavors and associated therapeutic actions	Sour: astringency and consolidation. Sour herbs are often used to treat conditions with sweating, cough, diarrhea, emission, incontinence, and heavy menses.	Pungent: promote distributions and circulations, enhance qi and blood activities. Generally, pungent herbs are used to treat conditions in the superficial portion of the body and also blood or qi stagnation.
	Bitter: purge fire, dry dampness, promote bowel movements, and rectify qi movement. Bitter herbs are often used to treat conditions with fever, heat signs, asthma and coughing, vomiting, hiccup, constipation, qi stagnation, abdominal mass, and conditions due to excessive dampness or virtual fire.	Sweet: lubricate and nourish the body, neutralize toxic effects, slow down acute reactions and arrest pain. Sweet herbs are often used to treat general weakness, spleen and stomach disharmony and painful conditions. Some herbs can also induces urination and expel dampness out of the body, such as poria, polyporus and coix seed.
	Salty: dissipate accumulations, soften hardness and purgation. Salty herbs are often used to treat constipation, abnormal growths and accumulations.
The four movements and associated therapeutic actions	Sinking and descending: promote downward and inward movements. The herbs are often used in clearing heat, purgation, calming, stabilizing actions in the upper body, soothing abnormal qi movements (e.g. hiccup, vomiting and cough), arresting excessive discharges.	Floating and ascending: promote upward and outward movements. The herbs are often used in uplifting yang qi (e.g. to prevent organ prolapse), distributing, dispersing, inducing vomit, and opening up orifices.

By following these simple steps, TCM can help maintain the body's balance and health.When choosing herbs for treatment, it is essential to first identify the disharmony pattern and then select herbs with the appropriate natures, flavors and movements. For example, herbs like golden thread rhizome, honeysuckle flower and Chinese gentian root have a cold property; they have cooling and purgative effects which can be used in yang excess conditions. Fleeceflower root has sweet and warm properties, it can nourish yin and promote blood production; while rehmannia root has sweet and cool properties, it can cool blood and nourish yin, the two herbs are commonly used in yin deficient conditions.

Golden thread rhizome is bitter and cold in property	honeysuckle flower is sweet and cold in property	Chinese gentian root is bitter and cold in property
Fleeceflower root is bitter and mild warm in property	Rehmannia root has both bitter and sweet flavors, and is cold in nature