中醫觀點

Cooked herbal teas versus herbal extracts

Traditional prescriptions from Chinese herbalists/doctors are normally a pack of mixed herbs, and we boil the herbs in several bowls (rice bowls) of water for one or two hours to make one bowl of herbal tea. The doctor's prescription normally also specifies the number of bowls of water needed as it determines the cooking duration. Sometimes, the prescription may also specify that some special herbs have to be boiled for a shorter time and hence have to be put in the cooking pot at a later time. This process of herbal tea making has thousands of years of history.

Recently, herbal extracts become popular alternative forms of prescriptions. For people who cannot afford the time to cook their herbal teas, these herbal extracts, in the form of soluble powders, are very convenient because they don't need cooking and are simply consumed with hot or warm water. Typically, according to the doctor's prescription, a number of small plastic bags of extracts, each being one type of herbal extract, are given to the patient. For example, if the doctor prescribes "yu ping feng san" (玉屏風散) which is a very common prescription for strengthening body's defense, the patient would get three separate plastic little bags of herbal extracts corresponding to the ingredients of yu ping feng san, i.e., huang qi (黃芪), bai shu (白術) and fang feng (防風).

The principle of using herbal extracts assumes that the herbs "add" up to give the expected result. This seems very logical. If yu ping feng san (玉屏風散) has huang qi (黃芪), bai shu (白術) and fang feng (防風) as its three basic ingredients, then we may expect to fabricate yu ping feng san (玉屏風散) by putting the three herbal extracts together. However, experience from patients taking herbal extracts almost always suggests that herbal extracts are not as effective and sometimes totally useless!

Obviously, the manufacturing process of herbal extracts could be prone to altering the expected effects of the herbs. Moreover, the main fault is the "adding" principle when a combination of herbs is taken. The traditional prescription of yu ping feng san (玉屏風散) is always regarded as one formula (藥方), although it consists of three herbs. The making of yu ping feng san (玉屏風散) requires boiling of the three herbs together, and this process is indispensable, and the resulting medicine has a positive effect on body's defense. In terms of the herbal nature of yu ping feng san (玉屏風散), it is neutral to the body (i.e., neither warm nor cool). Thus, it is usually prescribed with additional herbs according to the patient's conditions. But when the three ingredients of yu ping feng san (玉屏風散) are taken without the boiling process, it is NOT yu ping feng san (玉屏風散) and does not have the same effect. In fact, huang qi (黃芪) separately is a warm herb!

The conclusion is: one plus one plus one should be another one, and we need to take the right one!

February 2011