Reflections on Prescribing Herbs
Exploit the benefit while controlling the harm—this is a point to which particular attention must be paid when using Chinese herbs. In fact, it applies more broadly: a good Western physician must consider the same thing. For example, when using aspirin, one must fully take into account the drug's tendency to cause gastrointestinal bleeding.
When I first began clinical practice, I did not understand that prescribing requires systematic consideration. In the course of treating the disease I often caused the patient a whole series of side effects. In Chinese medicine this is called "attacking what is not at fault": in treating an illness, the medication itself gives rise to drug-induced symptoms, bringing discomfort to parts of the body that were not diseased. Ideally, prescribing should not cause this at all. But achieving that requires a foundation of clinical experience and theoretical grounding.
For example, spleen-strengthening herbs tend to damage kidney water: because most spleen tonics promote urination, using them too much easily leads to insufficiency of kidney fluids. Aconite (Fuzi) has the reputation of drying up a person's fluids; purgatives carry the hidden risk of damaging central qi; blood-activating medicines can injure blood; yang-tonifying medicines can injure yin; and yin-nourishing medicines can impede the diaphragm. A good Chinese prescription therefore contains: herbs that treat the main disease, called the "sovereign" (jun) herb; herbs that assist the sovereign in exerting its effect, called "minister" (chen) herbs; herbs that further aid the sovereign and minister while controlling their harmful effects, called "assistant" (zuo) herbs; and a messenger herb that guides the therapeutic effect to a particular part of the body, called the "courier" (shi) herb.
The key to treating disease is to grasp the essential point, so the most important herb in a formula must be the one that eradicates the patient's root cause, and its dose should be large. Personally I like to use "paired herbs"—groups of herbs appearing together, such as Chenpi with Qingpi, Cangzhu with Baizhu, Fuling with Zhuling, Sanleng with Ezhu, and Baishao with Chishao. The advantage of this approach is that the dose of each single herb can be reduced without losing efficacy, while the risk of drug poisoning is greatly avoided. Although such a prescription ends up somewhat larger, the risk borne by the patient is smaller, and the physician's professional risk is much smaller as well.
After many failures and much reading, I gradually came to understand that Chinese medicine is at once complex and simple—a kind of medicine with its own aesthetic beauty. As long as the physician is willing to study deeply and reflect carefully, the clinical efficacy of the formulas he prescribes will keep improving and the side effects will keep diminishing.