The herbs that fall under this classification are common, namely, that they can induce their major action. For this reason, an illness that is treated by perspiration can be treated with this. Conversely, a patient with an illness that can be intensified by perspiration should avoid this class of herbs. If, for example, you catch a cold, herbs in this class would benefit you because, in order to overcome the common cold or the flu, it is necessary to induce perspiration. On the other hand, if you suffer from night sweats, excessive perspiration, or chronic diarrhea, which will have already drained off a great deal of water from your body, you should avoid herbs in this class as much as possible.
Herbs that induce perspiration are divided into two subclasses: herbs for symptoms characterized by cold sensations (namely, Chinese ephedra, lily-flowered magnolia, and purple perilla) and herbs for symptoms characterized by fever (namely, hare's ear, kudu vine, and mulberry-leaved chrysanthemum). Thus, if you are suffering from the common cold with chills, the first subclass of herbs should be used; but once you display high fever, the second subclass is recommended.
All classes of herbs have specific uses and also entail a few measures of precaution. The major uses for the class of herbs that induce perspiration are the common cold and the flu as well as many related symptoms, such as headache, fever, pain in the body, and a cough. In addition, this class of herbs is also frequently used to treat bronchitis, bronchial asthma, measles at an early stage, acute glomerulonephritis, and acute rheumatic fever.
There are four measures of precaution in using this class of herbs. First, herbs in this class are not good for chronic symptoms involving the internal organs. This is partly because such symptoms cannot be treated simply by inducing perspiration and partly because prolonged consumption of these herbs will weaken the body, which is not desirable for patients suffering from chronic diseases of the internal organs. Second, symptoms that have already dehydrated the body, such as vomiting, diarrhea, and bleeding, should not be treated by this class of herbs. Third, after taking this class of herbs, it is desirable to stay calm and keep warm so that perspiration will occur to a suitable degree, being neither excessive nor insufficient. Fourth, when a rather weak patient such as an older person takes this class of herbs to heal an illness, it is wise for him or her to consume some herbs under the classification of herbs to treat deficiencies, namely, class 16.
From the point of view of modern medicine, the class of herbs to induce perspiration performs two basic functions. First, the herbs in this class can expand blood capillaries in the superficial region of the body and activate the secretion of the sweat gland to reduce fever, get rid of toxins, inhibit bacteria, and strengthen the body's ability to ingest and destroy bacteria and defend itself against foreign invasion. Second, this class of herbs can increase glomerular filtration to remove excessive water from the body.