By Eric Brand

In the modern day, Fu Zi products derived from about 10 different processing methods can be found on the Chinese market, and four specific forms are listed in the Chinese Pharmacopoeia. The four forms listed in the Chinese Pharmacopoeia include: 1) Dan Fu Pian, 2) Hei Shun Pian, 3) Pao Fu Pian, and 4) Bai Fu Pian. These forms can be directly used in decoctions.

In the U.S. market, the main items seen are Hei Shun Pian (also called Hei Fu Pian) and Bai Fu Pian, although steamed Fu Zi (sold as Shou Fu Zi) and blast-fried Fu Zi (often sold as Pao Tian Xiong) can be seen as well. [Note: Bai Fu Pian, literally “white Fu Zi slices,” are sometimes mistakenly traded under the name Bai Fu Zi, which should correctly refer to a different medicinal- Typhonii Gigantei Rhizoma, which is also known as Yu Bai Fu.]

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Fu Zi is harvested from the end of June to early August, and the cleaned lateral roots are separated from the main root and rootlets. At this initial processing stage the item is known as “nifuzi,” literally “muddy Fu Zi.” Within the first 24 hours of harvest, the freshly-harvested roots need to be soaked in a solution of mineral salts to prevent rot. This mineral salt solution, known as “dan ba,” is a product that is traditionally used in Fu Zi processing to preserve the fresh roots and reduce toxicity; dan ba is an edible, salty mineral substance that is produced as a by-product of salt processing (basically the dregs after pure salt is made). Sichuan was historically a major center of salt production in China, and salt-processing for Fu Zi has been prevalent for centuries based on the concept that the salty flavor enters the kidney.

Yan Fu Zi: Yan Fu Zi is salted Fu Zi; it is not commonly used directly in decoctions, but rather is used to make further refined forms of Fu Zi such as Dan Fu Pian (desalted or bland aconite slices). Yan Fu Zi is made by selecting large, full roots of nifuzi, then soaking them overnight in a solution of mineral salts. Next, it is continually soaked in salt water and the roots are taken out each day to dry before being re-soaked in the salt water. This gradually prolongs the drying time. When the product is finished, it is firm and covered in salt crystals. At this stage, the item is still numbing to the tongue.

Dan Fu Pian: Dan Fu Pian, desalted or “bland” Fu Zi, is made by soaking Yan Fu Zi in clear water until the salt is removed; the water is changed 2-3 times per day during this process. Next, the Fu Zi is decocted with licorice and black beans until the core is reached and slices of the Fu Zi no longer numb the tongue. Then the licorice and black beans are removed and the Fu Zi is sliced into pieces and sieved clean. For every 100 kg of Yan Fu Zi, 5 kg of licorice and 10 kg of black beans are used. This form is considered to be best for treating yang desertion.

Hei Shun Pian: Hei Shun Pian is made by grading nifuzi pieces based on size, then washing the pieces and soaking them for several days in a solution of mineral salts. After soaking for several days, the roots are boiled thoroughly and then taken out and rinsed. The roots are then sliced into thin slices (0.5cm thick) and are then soaked again in water. The product can then be stained to the color of concentrated tea, and it is then steamed until it has an oily, lustrous appearance. Then it is oven-dried until half-dry, and either finished with oven-drying or air-drying. Hei Shun Pian is the most commonly-used form of Fu Zi, and it also tends to have the lowest toxicity.

Bai Fu Pian: Bai Fu Pian appears white because it has the black skin removed. It is made by taking washed pieces of nifuzi of uniform size and soaking them in a mineral salt solution for several days. It is boiled thoroughly in the mineral salt solution until the core is reached, and then it is taken out and its outer skin is manually removed. It is then sliced into thin slices (0.3cm thick) before being soaked in water, removed, and steamed. Next it is sun-dried, and sulfur is sometimes used when it is halfway dried.

Pao Fu Pian is made by stir-frying either Hei Shun Pian or Bai Fu Pian in hot sand at high heat until the Fu Zi slices puff up and change color. A similar product, often sold under the trade name Pao Tian Xiong, is made by baking whole, peeled pieces of Fu Zi until they puff up and change color. These forms are considered to be best for warming the kidney.

References:
Zhao Zhongzhen, Bai Yao Pao Zhi (Processing of a Hundred Medicinals), Wanli Press. Hong Kong, 2010.
Ye & Zhang, Zhong Yao Pao Zhi Xue (Chinese Medicinal Processing, second edition), People's Medical Publishing House. Beijing, 2011.
Jin Shi-Yuan, Zhong Yao Chuan Tong Jian Bie Jing Yan (Jin Shi-Yuan's Experience in Traditional Differentiation of Chinese Medicinals), China Chinese Medical Press. Beijing, 2010.
Zhao Z. et al., Toxicity Assessment of Nine Types of Decoction Pieces from the Daughter Root of Aconitum carmichaeli (Fu Zi) Based on the Chemical Analysis of Their Diester Diterpenoid Alkaloids, Planta Medica, 2010.