The Characters and Functions of Traditional Chinese Drugs

Each drug has its own specific characters. In traditional Chinese medicine, the different characters of drugs are employed to treat diseases, rectify the hyperactivity or hypoactivity of yin or yang, and help the body restore its normal physiological functions, consequently curing the diseases and restoring health. The various characters and functions of these drugs concerning medical treatment include drugs' properties, flavors, actions of lifting, lowering, floating and sinking, channel tropism, toxicity, etc. The theory of characters and functions of traditional Chinese drug is based on the theories of yin and yang, viscera, channels and collaterals, and treatment principles of traditional Chinese medicine, and has been developed and summed up throughout a long history of medical practice. This theory provides the basis for drug analysis and application.

1. Properties and Flavors of Traditional Chinese Drugs

Properties and flavors are also known as four properties and five flavors. Every drug has its property and flavor. Property refers to the cold, hot, warm or cool nature of a drug. These properties of drugs are so sorted out according to the different actions of the drugs on the human body and their therapeutic effects. For example, drugs that cure heat syndrome (yang syndrome) have a cold or cool property, whereas drugs that cure cold syndrome (yin syndrome) have hot or warm property.

Drugs of cold and cool natures and drugs of warm and hot natures are of opposite properties. A cold-natured drug is different from a cool-natured one only in degree, and so is a warm-natured drug from a hot-natured drug. Most of the cool- or cold -natured drugs have the effects of clearing heat purging fire, removing toxic substances, and nourishing yin, and are used to cure heat syndromes. On the contrary, drugs of warm or hot nature usually have the effects of dispersing cold, warming up the interior, supporting yang, and treating collapse, and are therefore used to treat cold syndromes. In addition to the four properties mentioned above, there is the fifth, the neutral or mild one. When a drug is neither hot nor cold in nature, it is said to be neutral. It can be used for either hot or cold syndromes. Yet, drugs of neutral nature usually tend to be either slightly hot or slightly cold. That is why drugs are generally said to be of four properties only.

Flavors refers to the tastes of drugs, i. e. pungent, sweet, sour, bitter, salty, tasteless and astringent. Since sweet and tasteless usually coexist, and since sour and astringent drugs have the same effects, pungent, sweet, sour, bitter and salty tastes are the cardinal flavors and are habitually known as five flavors. Drugs of different flavors and different compositions show different pharmacological and therapeutic actions, while drugs of the same taste usually have similarities in effect and even in composition. The flavors don't necessarily refer to the real tastes of the drugs. Sometimes they are sorted out according to drugs' actions other than tastes. Therefore, the flavors of some drugs described in books on materia medica are often different from their true tastes. Various flavors have different effects. They are explained separately as follows:

Pungent flavor: Drugs that are pungent in flavor have the effects of dispersing exopathogens from superficies of the body and promoting the circulation of the vital energy and blood. Pungent drugs are usually used for the treatment of superficial and mild illnesses due to affection by exopathogens, stagnation of vital energy, blood stasis, etc.

Sweet flavor: Drugs of sweet flavor have the effects of nourishing, replenishing, tonifying, or enriching the different parts or organs of the body, normalizing the function of the stomach and spleen, harmonizing the properties of different drugs, relieving spasm and pain, etc. Drugs of sweet flavor are usually effective in treating syndromes of deficiency type, dry cough, constipation due to dry intestine, incoordination between the spleen and the stomach, various pains, etc. Besides, some of the sweet drugs have the effects of detoxication.

Sour flavor: Drugs of sour flavor have the effects of inducing astringency and arresting discharge. Sour drugs are often used to treat sweating due to debility, chronic cough, chronic diarrhea, emission, spermatorrhea, enuresis, frequent micturition, chronic leukorrhagia, metrorrhagia or metrostaxis, etc.

Bitter flavor: Drugs of bitter flavor have the effects of clearing heat, purging fire, sending down the adverse flow of qi to treat cough and vomiting, relaxing the bowels, eliminating dampness, etc. Such drugs are mostly used for syndromes of pathogenic fire, cough with dyspnea, vomiting, constipation due to heat of excess type, damp-heat syndrome, or cold-damp syndrome and other syndromes.

Salty flavor: Drugs of this taste have the effects of relieving constipation by purgation, and softening and resolving hard mass. Salty drugs are mostly used in treating dry stool and constipation, scrofula, goiter, mass in the abdomen, and other problems.

Tasteless flavor: Drugs of this flavor have the effects of excreting dampness and inducing diuresis, and are commonly used for edema, dysuria and others.

Astringent flavor: Drugs of this flavor have similar actions as those of sour flavor.

Drugs of the same flavor generally have similar actions, and drugs of different tastes have quite different actions. Yet some drugs are the same in property but different in flavor, or the same in flavor but different in property, and, therefore, their effects are not all the same. Both coptis root and dried rehmannia root, for instance, have the same cold property, yet coptis root is bitter in flavor while dried rebmannia root sweet. The former has the effects of clearing heat and drying dampness and is used for damp-heat syndrome, while the latter has the effects of clearing heat and nourishing yin and is used for the condition of consumption of yin due to febrile diseases. Another example is the use of ephedra and peppermint, both of which have a pungent flavor. However, the property of ephedra is warm, whereas the property of peppermint is cool. The former has the effects of dispersing wind-cold pathogens and is used to treat exterior wind-cold syndrome, while the latter has the effects of dispersing pathogenic wind-heat and is used to treat exterior wind-heat syndrome. Therefore, the property and flavor of a drug should not be treated separately but should be taken into consideration as an integrated whole. Only in this way can drugs be understood and used correctly.