|
大黃 Dahuang
Chinese Name |
大黃 |
|
Chinese Pinyin |
Dahuang |
English Name |
Rhubarb Tangute Rhubarb |
Latin Pharmaceutical Name |
Rhei Radix et Rhizoma |
Category |
Roots and rhizomes
|
Origin |
The dried root and rhizome of Rheum palmatum L. or Rheum tanguticum Maxim. ex Balf, or Rheum officinale Baill. (Polygonaceae). |
Production Regions |
Primarily produced in the Chinese provinces of Gansu, Qinghai, Tibet, Sichuan. |
Macroscopic Features |
Sub-cylindrical, conical, oval or irregular lumps, 3~17cm long, 3~10cm diameter. Peeled outer skin, surface is yellowish-brown to reddish-brown, some with off-white reticular striations or scattered star spots (specific vascular bundle); brown remnants of outer skin, with mostly rope-holes and rough wrinkles. Firm texture, sometimes with a slightly loose center; fractured surface is pale reddish-brown or yellowish-brown and granular. Rhizome has wide pith, with star spots arranged in whorls or scattered; xylem of root is well developed, with radial striations, cambium is obvious, without star spots. Delicately aromatic odor; bitter and slightly astringent taste, sticky and gritty when chewed. |
Quality Requirements |
Superior medicinal material is firm, with a delicate aromatic odor and a bitter and slightly astringent taste. |
Properties |
Bitter, cold. |
Functions |
Relieves stagnation, clears dampn-heat, reduces fire, cools blood, eliminates stasis, relieves toxin. Apply to constipation induced by sthenic fever, heat and distention and full of chest, damp-heat diarrhea, jaundice, strangury, edema and sbdominal fullness, difficulty of urination, conjunctival congestion, swelling pain of throat, sor of mouth and tongue, vomiting due to heat stomach, apostaxis, cough with blood, epistaxis, hematochezia, hematuria, blood stasis, amenorrhea, postpartum stasis and pain, abdominal mass accumulation, trsumatic injury, carbuncle and ulcer due to heat toxin, erysipelas, empyrosis. |
Processed Form |
Sheng da huang (also called sheng jun): Clean the crude drug, grades with different size, moistens to even inner and outer moisture; slice into flakes or lumps and dry. Jiu da huang: spry sliced da huang with yellow rice wine, moistens with a cover, fry with slow fire, take out and cool (100 jin of da huang slices with 14 jin of yellow rice wine). Da huang tan: da huang slices fried with fast fire till inner and outer surface is burnt brown (keep its nature), spray with seldom water, take out and dry. |
Technical Terms |
‘Brocade pattern’: This refers to brocade-like reticulations seen on the exterior or the horizontally cut surface of da huang medicinal materials that are formed by interconnected off-white parenchyma, reddish-brown rays, and star spots. |
|
|
|
|
Permanent URL:https://sys01.lib.hkbu.edu.hk/cmed/mmid/detail.php?pid=B00006
|
|