Processing in Chinese materia medica is the technique of altering the properties of crude medicines by such means as roasting, honey frying, wine frying, earth frying, vinegar frying, calcining, or other means. This is a kind of alchemical processing used in everyday preparation of herbal, mineral and animal medicinals. There are also more esoteric traditions of processing, including those involving , but the term is used to refer to the more common preparations. For instance, frying with wine is believed to enhance the circulatory properties of herbs. Frying with salt is believed to draw the herbal actions to the kidneys. Otherwise cooling herbs may be warmed up by heated techniques. These techniques have been applied to Western herbal medicine in the David Winston Center for Herbal Studies for the last 20 years.
The technique is somewhat similar to the Ayurvedic , although the latter technique is more complex and may involve prayers as well as physical techniques. An intriguing study of the effectiveness of the Ayurvedic equivalent of Pao Zhi was printed in the Journal of Postgrad Medicine:
Crude aconite is an extremely lethal substance. However, the science of Ayurveda looks upon aconite as a therapeutic entity. Crude aconite is always processed i.e. it undergoes 'samskaras' before being utilised in the Ayurvedic formulations. This study was undertaken in mice, to ascertain whether 'processed' aconite is less toxic as compared to the crude or unprocessed one. It was seen that crude aconite was significantly toxic to mice whereas the fully processed aconite was absolutely non-toxic . Further, all the steps in the processing were essential for complete detoxification