Introduction of Bai Wei:Blackened Swallowwort Root or Radix Cynanchi Atrati.
✵The TCM herbalism is also known as pharmaceutics of Traditional Chinese Medicine, or Chinese pharmaceutics, is the branch of health science dealing with the preparation, dispensing, and proper utilization of Chinese herbs. It is majorly composed of Introduction of Chinese Medicinals, Classification of Chinese Herbs, Formulas, and Patent medicines.
Classifications of Herbs:Herbs Clearing Heat and Cooling the Blood.
Introduction:Herbs Clearing Heat and Cooling the Blood: an agent or substance herbs that has the effect of eliminating pathological heat from the nutrient and blood systems in cases of warm diseases marked by fever accompanied by delirium, eruptions and bleeding symptoms, and also in other diseases with bleeding due to heat in the blood.
✵Till the date Oct 10th,2019, there are totally  kinds of common TCM herbs,  kinds of related plant species, are recorded in this category. These Herbs Clearing Heat and Cooling the Blood. are briefly introduced separately:
Pin Yin Name: Bái Wēi.
English Name: Blackened Swallowwort Root.
Latin Name: Radix Cynanchi Atrati.
Property and flavor: cold, bitter, salty.
Brief introduction: The herb Radix Cynanchi Atrati is the dried root and rhizome of Cynanchum atratum Bge. Or Cynanchum versicolor Bge.(family Asclepiadaceae), used (1).to clear heat and cool blood for fever in cases of consumptive diseases or cases due to Yin deficiency, (2).to induce diuresis in cases of heat stranguria and bloody stranguria, and (3).to counteract toxins in cases of boils and sores. The herb is commonly known as Blackend Swallowwort Root, Root of Blackend Swallowwort, Root of Versicolorous Swallowwort or Bái Wēi.
Botanical source: The herb Radix Cynanchi Atrati(Blackened Swallowwort Root) is the dried root and rhizome of Cynanchum atratum Bge. Or Cynanchum versicolor Bge., they are plants of the Cynanchum Linn. Genus, the Asclepiadaceae family of the Contortae order.
Common official herbal classics and Other famous herbal classics defined the herb Radix Cynanchi Atrati(Blackened Swallowwort Root) as the dried root and rhizome of (1). Cynanchum atratum Bge. Or (2). Cynanchum versicolor Bge. These 2 commonly used species are introduced as:
(1).Cynanchum atratum Bge.: Botanical description: It is commonly known as Bai Wei, Blackend Swallowwort, also known as upright Blackend Swallowwort. Herbs perennial, 40~70 cm tall. Plant body with white milk. Rhizomes short, fasciculate with most slender strip roots, 20 cm or more in length, 2~3 mm in diameter, yellowish rind. Stem erect, green, cylindrical, usually unbranched, densely grayish pubescent. Leaves opposite; Shortstipitate; Leaf blade ovate, or ovate-oblong, ca. 5~10 cm long, ca. 3~7 cm wide, apex shortly acuminate, base rounded, entire, both surfaces covered with white tomentose, especially on the back and veins. Lateral veins 6~7 pairs. Flowers many, in the stem tip leaf axils into a dense umbel cyme; Pedicels absent, flowers purplish, ca. 10 mm in diameter; Calyx green, 5 deep outside tomentose, inner base with 5 small glands. Corolla amplitudes, 5-lobed, pubescent outside, ciliate; Corona 5-lobed, lobes peltate round, as long as the confluent column; Anthers apex with a circular diaphragm; Pollen mass 1 per chamber, pendulous, oblong-shaped dilated; The stigma is flat. Follicles solitary, 5~9 cm long, 5~15 mm in diameter, apex acuminate, base obtuse, middle dilated. Seeds numerous, ovoid, narrowly winged, ca. 4 mm long; Coat white, ca. 3 cm long. It is flowering from May to July, fruiting from August to October.
Ecological environment: the Cynanchum atratum grows on hillsides or forest edges. The plant mainly distributes in the north, central, and south, southwest area, the lower reaches area of the Yangtze River, and other areas of China.
Growth characteristics: The Cynanchum atratum prefers a mild and humid climate, with good drainage, fertile, deep soil layer, rich in humus sandy loam or loam is suitable.
Characters of herbs: The rhizome is often curved, stubby, knotted, 0.5~1.2 cm in diameter; There are several rounded concave stem marks at the top, or a short stem base, most fibrous roots clustered below and on both sides. Root cylindrical, slightly curved, shaped like a horsetail, 5~25 cm long, 1~2 mm in diameter; The surface is yellowish-brown to brown, with fine longitudinal wrinkles or smooth, brittle, broken, flat section; Skin developed, yellow-white to yellowish-brown; Small wood, yellow. Slight odour, slightly bitter taste.
Pharmacological actions: The radix cynanchi atrati has an inhibitory effect on pneumococcus, clearing heat and diuresis, and it can enhance the contractility of myocardium.
Medicinal efficacy: Clear heat and benefit Yin, diuretic and treating stranguria, detoxify and cure sores. It is indicated for warm heat disease, fever and macula, hot flash and bone steaming, lung heat and cough, postpartum dysphoria, pyretic stranguria, bloody stranguria, swelling and pain in throat, sore carbuncle and pyogenic infections, snake bite.
Administration of Radix Cynanchi Atrati(Bái Wēi):
Administration Guide of Radix Cynanchi Atrati(Bái Wēi)
Internally:4.5~9 grams(CP),Internally:water decoction, 1.5~3 qian(about 4.5~9 grams), or prepare to pill,powder(DCTM),Internally:water decoction, 3~15 grams, prepared to pill,powder(CHMM).
(2).Cynanchum versicolor Bge.: Botanical description: It is commonly known as Wan Sheng Bai Wei, or Versicolorous Swallowwort, similar to Blackend Swallowwort, which differs in that the plant does not have white milk, the upper part of the stem is twined and the lower part is erect, and the leaf texture is relatively thin. Flowers small, yellowish-green, gradually purple, corolla lobes inner surface pilose.
Ecological environment: the cynanchum versicolor grows in the mountain bush, grows on the vine, it mainly distributes in the lower reaches area of the Yangtze River, middle to lower reaches area of the Yellow River, and other areas of China.
Characters of herbs: The root and the remaining stem base are thin and more curved. Root thick long, uniform, yellow-brown color is better.
1.Introduction of Bai Wei:Blackened Swallowwort Root or Radix Cynanchi Atrati.
2.TCM Books:DCTM(Dictionary of the Chinese Traditional Medicine),CHMM(Chinese Herbal Materia Medica).