Bai Shao and Chao Bai Shao. For more pictures of pao zhi herbs, follow the #paozhi tag on twitter
Pao Zhi 炮制 refers to the preparation of Chinese medicinal herbs. All herbs are prepared in one way or another by the time they appear in your local Chinese herb pharmacy. Some are simply washed, cut in a particular way and dried. Others undergo a more intensive preparation process to reduce toxicity and enhance medicinal effect.
Ban Xia 半夏, for instance, is prepared with either lime (calcium oxide) or ginger juice for several days before it takes on the appearance we're used to seeing. Turning Sheng Di Huang 生地黄 into Shu Di Huang 熟地黄 involves steaming the cut pieces over wine for several hours until they become much darker and deeper black (if you have an I.D. test, don't fret over Sheng Di vs. Shu Di - Sheng Di usually always has a little bit of brown somewhere on it. Shu Di will be deep black all over).
Other herbs can be processed with liquid adjuvants. The most obvious example is Gan Cao 甘草 and 炙甘草 Zhi Gan Cao. Zhi Gan Cao, of course, is prepared with honey, making it much sweeter and a stronger qi tonic than regular Gan Cao (or Sheng Gan Cao 生甘草, as it's sometimes called, to distinguish it from its honeyfied cousin). Cu Chao Chai Hu 醋炒柴胡, or vinegar-fried bupleurum, is used to direct the action of the herb to the Liver channel (because vinegar is sour and sour is the flavor associated with the Wood phase) and according to Bensky enhances the ability of Chai Hu "to soothe the Liver, harmonize the blood, and stop pain." I would guess that it also warms the herb considerably (regular Chai Hu is cool to cold).
Fat Turtle Herb Company makes many of these herbs available for your use as practitioners. Below is a short summary of the major differences between the processed and unprocessed versions of some of these herbs. For more information in English take a look at Philippe Sionneau's pao zhi book, translated by the ubiquitous Bob Flaws. The end section of each herb monograph of the third edition of the Materia Medica by Bensky et al also has good information on different herb preparations. I haven't had a chance to look at it yet, but I would be surprised if Eric Brand and Nigel Wiseman's Concise Materia Medica didn't have some excellent info on pao zhi as well.
- Bai Shao: Bitter and sour, slightly cold. Settles the Liver, downbears yang, nourishes the Liver, restrains yin.
- Chao Bai Shao: Bitter, sour, astringent, neutral temperature. Soothes the Liver, harmonizes the Spleen, stops diarrhea.
- Bai Zhu: Sweet, bitter, warm. Fortifies the Spleen, dries dampness, disinhibits urination, disperses swelling. Better at drying dampness.
- Chao Bai Zhu: Sweet, bitter, warm. Fortifies the Spleen, supplements the qi. This is a better Spleen qi tonic.
- Huang Qi: Sweet, slightly warm. Secures the exterior, stops perspiration, disinhibits urination, disperses swelling, outthrusts pus and toxins.
- Mi Zhi Huang Qi: Sweet, slightly warm, slightly moistening. Supplements Lung qi, tends to moisten dampness, supplements vacuity.
There are many more pao zhi preparation available. Licensed acupuncturists and students at TCM colleges call 310-691-5226 or email firstname.lastname@example.org to check if the herb you want is available.
Note: granule practitioners don't feel left out! We have many pao zhi preparations available in granule format as well.