Xu Duan (Top 4 from Sichuan, Bottom 3 from Hanzhong) (Cylindrical and flat, grayish-brown, with longitudinal lines)

Hankou Xu Duan Slices

Sichuan Xu Duan Slices

Han Xu Duan

【Naming】

Xu Duan

 【Source】

Classified as Superior in the Classic of Herbal Medicine

 【Frequency of Use】

B

 【Botanical Origin】

The root of Dipsacus asper Wall. or Dipsacus japonicus Miq. of the Dipsacaceae family.

 【Characteristics】

It is long cylindrical, or slightly curved, 7-10cm long, 1-1.5cm in diameter, the surface is grayish-brown, with twisted longitudinal wrinkles and shallow grooves, lenticels are transversely cracked, and there are a few root scars. The texture is soft and not easy to break.
Prepared slices are longitudinal or transverse thin slices, about 1-3mm thick, with irregular edges. The cut surface has brownish-black irregular ring patterns, separating the cortex and xylem. The cortex is dark brown, the xylem is light brown, and there are off-white spots. The width of the cortex is about half of the xylem, and the vascular bundles are arranged radially, slightly showing dark green. It has a slightly fragrant odor, and tastes bitter, sweet, and astringent.

 【Processing】

1. Raw Xu Duan 2. Stir-fried Xu Duan 3. Wine-processed Xu Duan 4. Salt-processed Xu Duan.

 【Identification】

《Zheng Lei Ben Cao》: “But the one with broken sections and wrinkled yellow skin is genuine.” 《Ben Cao Gang Mu》: “The one that is red and thin, and produces smoke and dust when broken is better.” 《Ben Cao Gang Mu》: “[Hong Jing said] The light and thin one with a deep color is superior,” “[Song said] The one produced in Sichuan with thick flesh and deep color is better,” “The one with tight, thick two or three parts of the skin, and bright yellow is the best.” 《Ben Cao Bei Yao》: “The one produced in Sichuan is good, shaped like chicken feet, with wrinkled yellow skin, and broken sections is genuine.” 《Pao Zhi Quan Shu》: “The one used by people today, coming from Zhou, red and thin in color, and producing smoke and dust when broken is better.” 《Ben Cao Qiu Zhen》: “The one produced in Sichuan is good.” The one that is thick, firm, easy to break, yellowish-brown on the outside, and grayish-green on the inside is preferred.

 【Identification Terminology】

1. Zheng Ti (正提): The third-grade specification of Xu Duan medicinal material product. The root is completely dry, orchid-green, and as thick as a little finger.
2. Zheng Duan (正斷): The first-grade specification of Xu Duan medicinal material product. The root is completely dry, thick, soft, emerald green, and as thick as a thumb.
3. Dou Qing Cha (豆青碴): Xu Duan becomes hard after being stored for a long time, is easy to break, the fracture surface is uneven, the outer edge of the cortex is brown, and the inside is dark green, called Dou Qing Cha.
4. Mian Duan (面斷) (Fu Duan (副斷)): The second-grade specification of Xu Duan medicinal material product. The root is completely dry, soft, emerald green, and as thick as a middle finger. Also known as “Fu Duan”.
5. Fu Ti (副提): The third-grade specification of Xu Duan medicinal material product. The root is completely dry, orchid-green, and as thick as a cigarette.

 【Category】

Roots