Most of the Chinese herbs gathered are crude drugs. Many Chinese herbal medicines need to be processed to bring out their full efficacy. Herb processing, known aspaozhi ,xiushi orxiuzhi in ancient times, refers to the processing of original Chinese medicinal materials, whenever necessary, according to the needs of the medical treatment, prescription, modulation, storage and characteristics of the medicinal materials.
What are the main methods of herb processing?
There are five methods of processing Chinese herbs, namely regulating , processing with water , processing with fire , processing with both water and fire , and processing with other materials.
•Regulating : to prepare for further processing, storage, adjustments, preparation and usage as clinical medicines. Includes three working procedures of purifying , grinding and cutting of the medicinal materials.
•Processing with water : water or other liquids are used to cleanse and soften the herbs to make cutting and modification of the herb easier. Some common processing methods are rinsing , immersing , moistening , spraying and water suspension grinding .
•Processing with fire : fire is used to provide heat during the processing of herbs. This is the most common method of herb processing. Methods include toasting , stir-baking with adjuvant , calcining , roasting in hot ashes and baking .
•Processing with both water and fire : includes methods such as steaming , boiling , stewing , scalding , tempering , etc.
Other methods of processing include degreasing , fermenting , germinating , etc.
What is the purpose of processing Chinese herbs?
- To reduce toxic side-effects of the medicine. E.g. frankincense and myrrh cause nausea and vomiting when taken raw, but after toasting , such reactions are reduced.
- To change the properties of herbs. E.g. dried rehmannia root has a cool property, having a cooling effect on the blood. After processing, it becomes warm in nature and helps to enrich the blood.
- To enhance curative effects. E.g. after toasting corydalis tuber with vinegar, it becomes more effective in relieving pain.
- To guide medicine into the meridian, directing therapeutic effects to targeted areas more easily. E.g. toasting bupleurum root , green tangerine and nutgrass flatsedge rhizome with vinegar will help to guide medicines into the liver meridian.
- To purify the medicine. E.g. animal medicines carry foul and unpleasant odours which can be removed through processing.