Da Huang (Rhubarb)

This product is commonly used in traditional Chinese medicine. It was first published in "Shen Nong Ben Cao Jing", where the herb is named (Da Huang means big and yellow) because of its large size and yellow coloring.

Alias: Chuan Jun, Mian Wen, Sheng Jun.

Source: Rheum palmatum L. Rheum tanguticum Maxim. ex Balf or Rheum officinale Baill of dried roots and rhizomes, wild or cultivated.

Overview: Rhubarb is widely distributed, with Qinghai, Gansu, Sichuan as the main production areas, in addition to Yunnan, Guizhou, Hubei, Shaanxi and other places which also produces the herb, due to the different production areas, varieties, wild and cultivation and processing methods, the characteristics of odor, color and luster are different, so there is a variety of specifications in history. In the past, the rhubarb produced in Gansu was named with place names, such as Wu Du Dan Ji, Wen Xian Zhong Ji, Qing Shui Bian Zi, etc., and each was divided into several grades. Qinghai and Gansu products are mostly palm leaf rhubarb and Tangut rhubarb, while Sichuan and Yunnan are mostly medicinal rhubarb. However, the distribution area of the original plant cannot be completely separated, and Sichuan also has the distribution of palm leaf rhubarb. In order to simplify the cumbersome name, according to the various characteristics of commercial rhubarb, and to take into account the historical medicinal habits, the Ministry of Commerce issued the "Trial Standard for 100 Commodity Specifications of Three Categories of Medicinal Materials" in 1965, which summarized rhubarb into six varieties.

Trait identification:

1. Xi Da Huang (West rhubarb): refers to Qinghai, Gansu, Gannan Autonomous Prefecture, Minxian and other places produced wild varieties, commonly known as "Xining rhubarb", there are Dan Ji (even, neat, shaped like duck eggs), Pian Ji (root head, longitudinal cut petals are flaked), Zhong Ji (rhizome and leaves of the cross-cut section), Su Ji (refers to the tail root, slightly light, and has the original shape of the wedge), etc. The surface is yellowish-brown, and each piece has a small hole which is used to rope up the herb for drying. The weight is solid, the section is like a betel nut, showing red meat and white tendons, and the texture is clear and not messy (cotton grain). The smell is fragrant, biting will have a grit feeling, and the taste is sweet and slightly bitter. It is an excellent product in rhubarb.

   Xining rhubarb is divided into two specifications: Xiang Huang and Bao Huang, and the diameter of Xiang Huang shall not be less than one inch (if the middle section and coarse tuber ballast are not good, it is not considered Xiang Huang) clean the coarse skin and fine skin. There are middle nodes or root lumps in the Bao Huang, when the cork is removed, the surface is yellow-brown and dark brown, and the weight is loose. The section is red and white (betel nut) or yellow, the texture is red and white, the fragrance is the same as with the Xiang Huang, the length is different, but the diameter shall not be less than 5 fen. No more than 15% of the heart should have sugar and bran like appearance.

2. Liang Da Huang: refers to the wild products produced in Wuwei (Liangzhou), Zhangye and Hexi areas of Gansu Province. The rhizome is irregular and lumpy like a dog's head (commonly known as Gou Tou rhubarb (“Gou Tou” meaning dog's head in Chinese)), or cut longitudinally into petals without cork. The surface is black-brown, with transverse wrinkles and longitudinal grooves, and the weight is firm. The section is red and white (betel nut ballast) with red meat and white tendons, and the texture is chaotic. The air is fragrant, and the taste is sweet and bitter. The tooth bite is more gritty, and has a sticky tooth feeling, is of excellent quality, and is considered a treasure in rhubarb.

3. Quanshui Da Huang: refers to Gansu Lixian, Minxian, Danchang, Wudu and other places (cultivated products) divided into four levels: Dan Ji, Pian Ji, Zhong Ji, Su Ji. Removed cork skin, yellowish-brown surface, solid weight. The cross-section is red and white (betel nut ballast), the ray texture is clear, the vortex ray dots are many, in an irregular ring arrangement, the air is fragrant, the taste is slightly bitter, and it is also an excellent product in rhubarb. Because of its good red coloring. It is mainly used for export.

4. Wen Da Huang: refers to the Wudu area of Gansu Province and the adjacent areas of Sichuan and Gansu, including Qingshui. It is a longitudinally cut lobe or transversely cut segment of a rhizome. Remove the cork skin. The surface is yellow or yellowish-brown, and the quality is firm and weight-heavy. The section is red and white (betel nut) or yellow, fragrant, bitter and astringent. The quality is slightly inferior.

5. Ya Huang: refers to the wild products in western Sichuan, Derge and Yunnan. The goods are horseshoe-shaped blocks and are divided into four classes. 1·2. Wait to remove the cork skin. The surface is yellow or yellowish-brown or yellow-green inside and out. The quality is strong or the weight is relaxed. There is no texture of red meat and white tendons in the cross-section. 3·4. Do not remove no cork. The surface is brown, with transverse wrinkles, the texture is light or lightly foaming, and the section is yellow-brown or greenish-brown. The 4th grade is irregular block, the size is not distinguished, and the root is yellow. (The breath is slight and the taste is bitter. Customarily thought of as inferior quality. ）

6. Nan Huang (Southern rhubarb): refers to the Yahuang cultivation products in the adjacent areas of eastern Sichuan and Hubei, Guizhou and Shaanxi. The rhizome is cut crosswise into segments and the cork is removed. The surface is yellowish-brown, and the quality is firm and weighty. Yellow or yellow-green in section. The aroma is astringent and bitter.

In addition, there are:

1. Shui Gen Da Huang (Water-root rhubarb): It is processed from the thinner branch root of rhubarb and the tail section of the taproot. The diameter is about 2cm, and the length is about 5~10cm. The cork skin is not cleaned. The surface is yellowish-brown, often wrinkled. The section is cotton-grained, and some of the ballast is black-brown. It is considered a defective product of Gansu rhubarb.

2. Tibetan rhubarb: Some of the products in Qamdo are similar to Ya Huang, but in recent years, the specifications of the products in the new exhibition areas such as Nagqu and Nyingchi have not yet been finalized. Most of them are long lobes, 6~15cm long, about 3~6cm in diameter, with skin or cork scraped off. The surface is brown or brown, mostly hung with ropes, dried in the shade or sun-dried, and the inner ballast is more cotton-grained. Due to the lack of strict control of the excavation time, the color of the ballast is different, and the quality is not equal. In addition, the species of the original plant are messy, and some non-medicinal rhubarb is mixed in, which needs to be improved in the future.

All kinds of medicinal rhubarb are preferable to those with solid physique, uniform cutting petals, cross-sectional betel nut ballast, fragrant, sweet, bitter but not astringent.

Main ingredients:

（1）  Anthraquinone derivatives, content 2~4%, including emodin, chrysophanol, rhein acid, aloe emodin, etc.;

（2）  Rhubarb tannins, mainly glucose galloside tannins. It also contains free gallic acid.

Pharmachologic effect

（1）  Laxative: Rhein acid is the main active ingredient of laxative, which can stimulate the large intestine, increase its propulsive peristalsis and promote defecation, the effect is relatively gentle, and the soft muddy feces or porridge-like loose stools are discharged about 6 hours after taking it, and it will stop after the next time. There may be no abdominal pain before and after defecation, or only mild abdominal pain, and the combination of qi medicine (such as Hou Pu) can strengthen diarrhea and reduce the side effects of abdominal pain.

（2）  Antibacterial: The active ingredient is anthraquinone derivatives, among which rhein acid, emodin and aloe emodin have strong antibacterial effect. The most sensitive bacteria in vitro tests are staphylococcus and streptococcus, followed by diphtheria bacillus, typhoid bacillus, paratyphoid bacillus, pneumococcus, dysentery bacillus, etc. The principle of antibacterial is that these anthraquinone derivatives have a significant inhibitory effect on the synthesis of nucleic acids and proteins in bacteria.

（3）  Astringency: Due to tannic acid, rhubarb often tends to cause constipation after diarrhea. Hence it tends not to be used long term.

（4） Stomach: Take its bitter taste to strengthen the stomach, and take a small amount of powder (0.6~0.9g) to work.

（5）  Choleretic: Experimentally proven to significantly increase bile flow, suitable for the treatment of gallstones.

（6）  Anti-tumor: Animal experiments have proved that rhein and emodin have obvious inhibitory effects on melanoma in mice, emodin on mouse breast cancer, and rhein on Ehrlich's cancer (ascites type). However, single rhubarb has not been used as an anticancer drug in clinical practice (though rhubarb is used in some anti-cancer Chinese medicine formula combinations).

Preparation: sliced, raw. Stir-fry in wine, vinegar, charcoal. Cut into 1 cm pieces, add wine and steam (cooked army).

Taste: bitter cold.

Meridians: Spleen, stomach, large intestine, liver, pericardial meridians.

Function: Diarrhoea and heat to clear the intestines, and remove stasis and accumulation. Apply externally to clear fire and reduce swelling.

Indications: Gastrointestinal heat stagnation, blood heat syndrome, jaundice, edema, blood stasis accumulation. Externally applied carbuncle swelling and sores poison, water and fire burns.

Clinical application: mainly used for laxative, diarrheal fever and anti-inflammatory.

（1）  It is used for constipation. In the middle or extreme stage of many febrile infectious diseases (such as lobar pneumonia and epidemic meningitis), when constipation, chest and abdomen fullness, high fever, delirium, thirst, tongue coating and other real heat syndromes appear, rhubarb can be used to wash away the accumulated heat, often with Zhi Shi and Hou Pu, such as Xiao Cheng Qi Tang decoction, or with other heat-clearing medicines, such as Liang Ge San. If the water loss is serious, it is necessary to prepare yin medicine such as Sheng Di, Mai Dong, etc., such as increasing Zeng Ye Cheng Qi Tang formula.

  After taking the above-mentioned laxatives, patients often receive the effect of reducing fever and improving their general condition, and the principle may be due to: (1) rhubarb itself and other heat-clearing drugs have antibacterial and anti-inflammatory effects; (2) when constipation, due to the absorption of toxins produced by intestinal putrefaction into the blood, aggravating the general discomfort, this adverse effect can be eliminated after laxative; (3) after laxative, it can relieve symptoms such as abdominal fullness and stuffiness, and make patients feel light.

（2）  It is used to treat damp heat jaundice. If you suffer from acute infectious hepatitis, or even subacute yellow liver atrophy, jaundice, abdominal distension, and constipation, you can use rhubarb, with Zhi Zi, Yin Chen, Hou Pu, Zhi Shi, etc., which has the effect of reducing inflammation and clearing heat.

（3）  It is used in the early stage of hot diarrhea (such as acute enteritis, bacterial dysentery, etc.). At this time, although the patient has diarrhea, but the diarrhea is not clear, the stool is not smooth, and there are putrefactive substances and inflammatory lesions accumulated in the intestines, and the tangible putrefactive deposits in the intestines can be discharged with rhubarb, which is conducive to inhibiting the reproduction of bacteria and controlling inflammation. This use of rhubarb is called "opening flow" to stop diarrhea. For example, in the early days of treating fever and dysentery, there was rhubarb. However, it should be noted that in the later stage of hot diarrhea, when there is only inflammatory discharge, rhubarb should not be used.

（4）  It is used for cold accumulation constipation. For the treatment of constipation and abdominal pain and systemic deficiency and cold syndrome, rhubarb can be used, with warm cold medicine Fu Zi, Xi Xin, etc., to dissipate cold, laxative, and relieve pain, such as used in Da Huang Fu Zi Tang formula.

（5）  It is used for the treatment of acute ocular conjunctivitis, upper respiratory tract inflammation and other so-called "blood heat" syndromes. At this time, if you have symptoms such as fever, head swelling and red eyes, and swollen throat, you can reflexively reduce the congestion of the head and face by using rhubarb to congest the abdominal cavity and reflexively reduce the congestion of the head and face, thus helping to reduce the above inflammation. It is used with Huang Qin, Huang Lian and other heat-clearing medicines, and the heavier ones are dispersed with Liang Ge San formula.

（6）  It is used to cool blood and stop bleeding, and treat fever bleeding. For example, hemorrhoids and bleeding are caused by hot stool and intestinal heat stagnation, 12~15g of rhubarb should be decocted in water; If they also have nosebleed, can add Sheng Di Huang 9g to decoct in water then add powdered Da Huang into it.

（7）  It is used for the treatment of gallstones or bile duct stones. With Jin Qian Cao, Zhi Zi, Zhi Ke, etc. (see Jin Qian Cao for details).

（8）  It is used for the treatment of bruises, and it has the effect of invigorating blood circulation and removing stasis (adjusting blood flow distribution). For example, after abdominal contusion, blood stasis and stool, 3~4.5g of rhubarb can be added to the Die Da Fang Ji formula, or raw rhubarb can be used alone to mix with wine. The very fine powder of rhubarb and licorice (10:2) can also be used to treat ulcers in the lower limbs.

Use caution

（1）  Raw rhubarb has strong laxative power, which is suitable for clearing laxative  with solid heat heat, and has a better anti-inflammatory and blood activation power after making wine, and either it or processed rhubarb would be more suitable for body weakness than raw rhubarb.

（2）  It should be used with caution before pregnancy (because it has the effect of promoting uterine contraction), should be used with caution after childbirth and during menstruation (because it can aggravate pelvic congestion), and should not be used by lactating women (because rhubarb is absorbed in the intestine and distributed to breast milk with blood flow, affecting the fetus.) If a breastfeeding woman takes more rhubarb, the milk will also turn yellow).

（3）  For laxative, rhubarb should not be cooked for a long time, so it must be lowered, and used to clear dampness and heat, the decoction time can be slightly longer.

（4）  Habitual constipation is generally not suitable for rhubarb, and so more moistening herbs would be used instead.

Dosage: The usual amount is 3~12g. Diarrhea often uses 9~12g, if it is equipped with qi medicine, sometimes only 6g can be used, if used to strengthen the effect of other attacking drugs, more than 12g may be used. The dosage of dampness and heat and anti-inflammatory should be small, 6g for adults, 3g for children, and 0.9~1.2g for young infants.

Prescription examples

（1）  Xiao Cheng Qi Tang (from "Shang Han Lun"): 12g Da Huang (entered last), 6g of Hou Po, 9g of Zhi Shi, decoction in water.

（2）  Liang Ge San ("Ju Fang"): raw rhubarb 9g (entered last) Mang Xiao 9g (Powdered and added into decoction) Zhi Zi 9g, Lian Qiao 9g, Huang Qin 6g, Bo He 3g (entered last), Zhu Ye 6g, Gan Cao 6g, decoction in water.

（3）  Zeng Ye Cheng Qi Tang ("Wen Bing Tiao Bian"): Xuan Shen 30g, Sheng Di 24g, raw rhubarb 9g (entered last), Mang Xiao 4.5g (powdered and added into decoction), decoction in water.

（4）  Da Huang Fu Zi Tang ("Jin Kuo Yao Luo"): Da Huang 9g (entered last), Fu Zi 9g, Xi Xin 3g, decoction in water.

Notes: Tu Da Huang (Earth rhubarb): alias Yang Ti, Niu Xi Xi. It is the dried root of the perennial herbaceous plant Rhubarb of the family Tateaceae. It is produced in the whole country, and it is distributed in Tianjin and Beijing, and it is wild. The taproot conical shape is divergent. The surface is brown, with striation, hard, pale yellowish-white section, showing radial texture. Bitter taste. It has the effect of clearing heat, stopping bleeding, killing insects and curing ringworm.

According to the record of "Tianjin Chinese Herbal Medicine", this product is suitable for patients with various bleeding diseases, such as lung, kidney, intestine, uterus, urinary bleeding and trauma, etc., decoction or injection injection, all have good hemostatic effect.

Non-medicinal rhubarb

This product is the root and rhizome of Rhubarb and plants of the same genus. It is mostly for export and sales abroad, wild or cultivated, such as wild Zi Huang in Shanxi and Hebei, and cultivated Tai Huang and Qi Huang. Wild Yu Huang in Shaanxi and Zhuang La Da Huang in Inner Mongolia and Gansu. The properties of these products, most of which are segmental, have been and with cork scraped off. The surface is yellow or yellowish-brown. The section is purple-brown-red or light yellow-brown, showing brocade lines, radial texture, and several layers of concentric rings, without vortex stars. The smell is peculiar, fishy, and bitter. Exported as a raw material for industrial dyes.

According to experience, this product is too strong, has lasting strength, and makes people feel intestinal distension and pain after taking it, so it is not medicinal. However, in a few areas, it is used as a veterinary laxative. Whether the original plant family and chemical composition of the above several non-medicinal rhubarb species are the same need to be studied in the future. According to the records of "Zhong Yao Zhi", this product shows blue-purple fluorescence under fluorescent light.

Disclaimer: All above articles are for reference only. If patients are interested, please consult a professional practitioner Traditional Chinese Medicine for a consultation.