Cynanchum atratum, Bai Wei 白微
Blackened Swallow-wortBai Wei (TCM)
Botanical name:
Cynanchum atratum, C. versicolor
Local varieties used include C. inamoenum, C. paniculatum, C. amplexicaule
Parts used:
Root
Temperature & Taste:
Cold, neutral in respect of dryness/moisture. Bitter, Salty
Classification:
B. Clears Deficient Heat
Uses:
1. Clears Heat, Cools the Blood:
-low-grade Fever; Chronic Fever, Yin-deficient Fever, Night-sweats
-persistent Summer Fever in Children
-lingering Fever after a febrile disease; recovery after Febrile disease
-Postpartum Fever
-Scrofula
2. Clears Heat, Promotes Urine:
-painful, dribbling Urine
-Blood in the Urine
-especially for Urinary disorders following Childbirth
3. Clears Heat and Toxin:
-Toxic Sores (topically and internally)
-Swollen, painful, sore Throat
-Lung Heat Cough
-Snake Bite (topically and internally)
Dose:
3–12 grams (some sources state a maximum of 6 grams should be used to avoid damaging the Stomach)
Comment:
Medicines regarded as Bitter and Cold are usually drying. However, Cynanchum isn’t regarded as dry and doesn’t damage Yin, Blood or Essence. It is therefore suitable for cases with deficiency and chronic Fever where Yin is already compromised.
Preparation:
1. In cases with Stomach weakness, it can be dry-fried to reduce its coldness.
2. Stir-fried with Honey until dark yellow. This makes it more moistening, better for the Lungs, for coughing Blood and for Night-sweats.
Substitute:
Tylophora ovata is considered an equivalent plant.
Main Combinations:
1. Acute Wind-Heat with Yin deficiency:
i. if Heat is more severe and Yin deficiency in mild, Cynanchum atratum with Artemisia annua Qing hao
ii. if Yin deficiency is more severe and Heat in mild, Cynanchum atratum with Soloman’s Seal (Yu Zhu) and Mint (Bo He)
2. High Fever from Heat entering the Nutritive level, Cynanchum atratum with Rehmannia Sheng Di Huang, Paeonia rubra Chi Shao Yao, Water Buffalo horn (Shui Niu Jiao)
3. Chronic and Low-Grade Fever, Yin Deficient Fever, Night sweats:
i. Cynanchum atratum with Lycium bark Di Gu Pi
ii. Cynanchum atratum with Phellodendron Huang Bai, Anemarrhena Zhi Mu, Lycium bark Di Gu Pi
4. Aftermath of Febrile disease, Chronic Fever, Postpartum Fever, Cynanchum atratum with Dang Gui and Ginseng.
5. Cough from Lung Heat, Cynanchum atratum with Scutellaria Huang Qin, Mulberry bark (Sang Bai Pi)
6. Consumption, Hectic Fever, Cynanchum atratum with Lycium bark Di Gu Pi and Hops (Lu Cao Guo)
7. Painful dribbling Urine during Pregnancy or Postpartum, with or without Blood, Cynanchum atratum with Paeonia Bai Shao
8. Acute Urinary infections, Cynanchum atratum with Plantain (Che Qian Cao)
9. Strangury:
i. from Heat and Damp, Cynanchum atratum with Plantain seed (Che Qian Zi), Akebia Mu Tong, Phragmites Lu Gen.
ii. with Blood, Cynanchum atratum with Crisium Xiao Ji, Gardenia Zhi Zi
10. Postpartum Fever:
i. Cynanchum atratum with Ginseng and Dang Gui
ii. Cynanchum atratum with Gypsum (Shi Gao), Bamboo shaving (Zhu Ru), Cinnamon twig (Gui Zhi), Licorice (as in Zhu Pi Da Wan, from Jin Gui Yao Lue [Synopsis of Golden Chamber]).
11. Boils, Abscesses, Toxic Sores, Cynanchum atratum with Forsythia Lian Qiao, Dandelion (Pu Gong Ying).
12. Snake Bite, Cynanchum atratum is applied topically, and is decocted with Paris root (Chong Lou), Lobelia Ban Bian Lian, Cynanchum paniculatum Xu Chang Qing.
Cautions:
1. Toxic in overdose (30–45 grams). It contains cardiac glycosides. Side effects include nausea, vomiting, dizziness, headache, diarrhea.
Drug Interactions:
Should not be used with Heart medication due to cardiac glycosides.