Many diseases are caused by excessive heat inside the body. This class of herbs is capable of reducing excessive heat inside the body and is used for diseases that are mostly characterized by inflammation or infection. This class is divided into three subclasses: herbs to reduce the "heat of fire" (namely, carrizo, cork tree, goldthread, purslane, selfheal, skullcap, and wind weed), herbs to reduce heat in the blood (namely, Chinese pulsatilla and white rose), and herbs to reduce heat and detoxify at the same time (namely, Asian dandelion, chicken-bone grass, Chinese violet, Japanese honeysuckle, and puffball).
The concept of heat is unique in Chinese medicine, as it is believed to be the cause of many so-called hot symptoms. Herbs that can reduce the "heat of fire" are used to treat acute inflammatory and infectious diseases because acute diseases can be said to attack as fast as fire burning down a building. Such acute diseases include encephalitis, which is inflammation of the brain; pneumonia, which is inflammation of the lungs, and acute bronchitis, which is inflammation of the bronchial mucous membrane. Herbs that can reduce heat in the blood are used to arrest bleeding, such as with nosebleeds, discharge of blood from the mouth and vaginal bleeding. Herbs that can reduce heat and detoxify simultaneously are normally used to treat inflammatory and infectious diseases that are suppurative, such as many skin diseases, mumps, lymphangitis, mastitis, and appendicitis.
A few precautions should be taken when using this class of herbs. First, symptoms related to the common cold, flu, fever, or excessive heat in the body due to constipation should not be treated by this class of herbs. Second, herbs in this class tend to be hard on the stomach because they are not easily digested. Therefore, they can be taken with the class of herbs for promoting digestion if necessary (class 9). Third, this class of herbs can dehydrate the body, and for this reason, they can be taken with yin tonics, which consist of herbs to treat yin deficiency (class 16).
From the viewpoint of modern medicine, this class of herbs can be used to heal inflammation, counteract bacteria, arrest bleeding, reduce body temperature, increase urination, and activate the ureter. This explains why such herbs can effectively treat urinary stones.