Every substance in the Chinese herbal pharmacopeia innately has specific characteristics, tastes, temperatures, and actions. Not only do herbs have an inherent nature, but many substances also need to be prepared before use. This processing is known as, pao zhi (炮制).
Processing begins after the herb has been harvested, dried and cut. Pao zhi prepares the herb in order to minimize side effects, increases potency, directs its action to specific areas of the body, and increases or alters properties of the substance for use in a particular clinical presentation.
Common Preparations of Chinese Herbs
Here are a few common herbal preparations that your practitioner may use when prescribing a raw herbal formula.
A stir-fry technique without the use of oil that directs the action of the herb to the Spleen and Stomach systems to improve the digestion. While adding salt to the stir-fry directs the action of the herb to the Kidney system. This preparation can also support the yin and reduce fire.
Frying with liquid
Adding one of the items below to a stir-fry is a great way to support the properties of the particular herb.
- Honey: nourishes and moistens
- Vinegar: astringes, invigorates the blood, detoxifies, and has analgesic properties
- Wine: unblocks the channels, expels wind, and reduces pain
- Ginger juice: warms the stomach, alleviates vomiting, balances cold and bitter herbs that may upset the stomach
An herb is fried at an extremely high temperature so that it becomes dark brown or cracked. This technique reduces toxicity and moderates harsh properties.
Done in either water or some other medium, this technique can also alter the characteristics of an herb. For example, boiling an herb in vinegar can reduce toxicity.
The Preparation Can Change an Herb’s Effect
One example of how processing affects the properties of an herb is with rehmannia root or Chinese foxglove. In the Chinese herbal pharmacopeia, the raw form that has been simply prepared for ingestion is known as, sheng di huang (生地黄). This herb is in the clear heat and cool blood category. Like its category, this herb is cold in nature and has the function to treat warm diseases. It also has the function to nourish the yin and generate fluids. When sheng di huang is prepared with rice wine and steamed, it becomes shu di huang (熟地黄).Shu di huang falls into the tonifying category in the pharmacopeia. This version is slightly warm and has the functions to nourish the blood, yin, and essence. Both forms of rehmannia affect the blood, yin, and fluids and they are often interchanged depending on the nature of the condition, whether there is more heat or cold, more excess or deficiency.
Your Chinese medicine practitioner will always evaluate your specific condition in order to customize the most appropriate herbal formula and advise you on any processing techniques that you may use at home to support its efficacy if you have elected for raw herbs.