Cynanchum Paniculatum (Xuchangqing): Pain Relief, Itch Relief, Cough Relief, Calming, and Diuresis
The Chinese medicine Xuchangqing is the root and rhizome, or the whole herb with root, of Cynanchum paniculatum (Bunge) Kitagawa of the Apocynaceae family. Also known as Gu Duzhong or Shixia Changqing, it was first recorded in the Shennong Bencao Jing (Divine Husbandman Classic of Materia Medica) and has a very long history of use in TCM.
Traditional TCM holds that Xuchangqing is pungent in taste and warm in nature, entering the Liver and Stomach meridians. It dispels wind and dampness, moves qi and invigorates blood, relieves pain and itching, and detoxifies and reduces swelling. It is mainly used for wind-damp bi pain, low back pain, epigastric and abdominal pain, headache, toothache, traumatic pain, difficult urination, diarrhea, eczema, urticaria, and venomous snake bites.
The foremost effect of Xuchangqing is pain relief. Modern TCM textbooks classify it as a wind-damp-dispersing pain-relieving medicinal. Xuchangqing can be used to treat many kinds of pain—whether wind-damp bi pain, tumor pain, stomachache or toothache, women dysmenorrhea, or pain from traumatic injury.
The analgesic effect of Xuchangqing may be mainly related to the paeonol it contains, but experiments have also shown that after removing paeonol, Xuchangqing still has some analgesic effect, so it may contain multiple pain-relieving components. Besides relieving pain, Xuchangqing also has some antipyretic effect, significantly reducing fever induced in experimental animals by typhoid vaccine.
Xuchangqing also lowers blood pressure, counteracts myocardial ischemia and arrhythmia, lowers blood lipids, inhibits platelet aggregation, and has anti-inflammatory, antibacterial, and anti-allergic effects. So it can also be used for various diseases caused by hypertension, hyperlipidemia, myocardial ischemia, thrombosis, infection, and allergy—such as hypertensive headache, hyperlipidemic chest and arm pain, and urticaria. Traditional TCM holds that Xuchangqing relieves itching and can treat eczema, neurodermatitis, and urticaria; for skin diseases, part of the decoction can be taken internally and part used for external washing.
Beyond this, some TCM practitioners in clinical practice have found that Xuchangqing has a good calming effect and can treat headache, insomnia, forgetfulness, fatigue, and anxiety caused by neurasthenia. In the 1960s, scholars including Lin Yuxuan made powders, pills (honey pills), and capsules from the whole herb: powder 10-15g each time, twice daily; pills (each containing 5g crude drug), 2 pills each time, twice daily; capsules 10 pills each time, 0.5g per pill. Each 20 days constituted one course. Treating 300 neurasthenia patients, after 2-3 courses, headache was relieved in 274, anxiety in 251, forgetfulness in 243, and palpitations in 232. The Jilin Chinese Herbal Medicines also records using 15g of Xuchangqing daily brewed as tea to treat schizophrenia (crying, sadness, trance). These show that Xuchangqing can treat emotional disorders.
Scholars including Wang Zuxian and Hao Xianjun found in clinical practice that Xuchangqing has a good cough-relieving effect. Wang Zuxian found that adding Xuchangqing improved the efficacy in treating persistent cough. In treating wind-cold cough, Hao Xianjun combined Xuchangqing with Guizhi (Cinnamon Twig), Banxia (Pinellia), Fuling (Poria), and Zhiqiao (Immature Bitter Orange), with good results. The Guiyang Folk Herbal Herbs records that locals in Guiyang treat lung heat, night sweats, and cough with 6g each of Xuchangqing and Luxiancao (Pyrola), powdered and taken with soda water, with remarkable effect. The Qingdao Chinese Herbal Medicine Manual records a formula using 9g Xuchangqing decocted in water to treat bronchial asthma. Xuchangqing pain relief, spasm relief, and anti-inflammatory/antibacterial effects may be related to its ability to stop cough and calm wheezing.
Xuchangqing also stops diarrhea and dysentery; it has the alternative name Lizhicao (dysentery-stopping herb), and folk medicine in many places uses it to treat dysentery. TCM holds that Xuchangqing stops diarrhea and dysentery mainly because it drains dampness and promotes diuresis; this effect can also be used to treat ascites. The veteran TCM doctor Wang Zuxian used large doses of Xuchangqing when treating ascites due to cirrhosis. Another veteran, Ye Jinghua, also pointed out that Xuchangqing boosts qi and promotes diuresis, and activates blood and resolves stasis; he clinically often uses Xuchangqing to treat edema caused by kidney disease. The Anhui Chinese Herbal Medicines also records a formula for pyelonephritis: Xuchangqing, Mohanlian (Eclipta), and Bianxu (Polygonum aviculare) each 15g, Shichangpu (Acorus) and Haijinsha (Lygodium) each 9g, decocted in water.
Xuchangqing has low toxicity and is harmless to the body at normal doses. But it has an anti-early-pregnancy effect, with an effective anti-early-pregnancy rate as high as 88.76%, so pregnant women must not use it. The usual adult dose is 15-30g; for pain relief, it may be used up to 50g in large doses, with proportionate reduction for children.