The Effects of the Herb Xueyao (Nanocnide) in Clearing Heat, Resolving Toxin, Reducing Swelling, and Dispelling Nodules
In China's Yangtze River basin and South China there is a green herbal medicine called Xueyao, commonly used by folk green-herb doctors; it is the whole herb of Nanocnide pilosa of the Urticaceae family. This is not a commonly used Chinese herb, so it is not sold in pharmacies or TCM hospital dispensaries, but searching for its botanical name Nanocnide pilosa (pinyin: maohua diancao) on platforms such as Taobao will turn up sellers.Xueyao mostly grows at around 1200m elevation on hillside roadsides, near houses, and in damp spots in gardens; it is found in Jiangsu, Anhui, Zhejiang, Jiangxi, Fujian, Hubei, Hunan, Guangdong, Guangxi, Sichuan, Guizhou, Yunnan, and elsewhere. People in Guizhou call it Bosi Cao, people in Hubei call it Xiao Jiulongpan, people in Guangxi call it Biandi Hong or Tougu Xiao, people in Zhejiang call it Maoye Lengshui Hua or Hongxi Cao, and people in Fujian call it Lianxian Chuma.Xueyao is usually collected in spring and summer when growing vigorously, and used fresh or dried in the sun. This herb is sour and bitter in taste and cool in nature, with the effects of clearing heat and resolving toxin, reducing swelling and dispelling nodules, and stopping bleeding. Folk tradition uses it to treat lung-heat cough, lymph-node enlargement (scrofula), hemoptysis, burns and scalds, abscesses, traumatic injuries, traumatic bleeding, and snake and insect bites.Xueyao has three main uses: first, treating burns and scalds; second, treating lymph-node enlargement; and third, treating lung-heat cough and hemoptysis.Xueyao is a specific for treating burns. Take 500g of the whole Xueyao herb, soak it in 5000g of rapeseed oil for one week, and this medicinal oil can then be used to treat burns of all degrees—mild, moderate, or severe.Using the medicinal oil made this way to treat burns, the effective rate (cured or improved) can be as high as 87%. The medicinal oil made from Xueyao and rapeseed oil has the effects of moisturizing the skin, relieving pain, anti-inflammation, and promoting epithelial growth, and has no side effects.To use, spread the oil evenly over the wound, keeping the area moist. One can also soak gauze in the oil and cover the wound, or, after applying the oil, cover the wound with medical gauze. Change the dressing every 1–2 days. However, this medicinal oil has the problem of poor drainage when applied, making it hard to handle wound exudate; it works better when combined with other astringent herbs (such as calcined gypsum).Xueyao used alone treats lung-heat cough and hemoptysis. Hunan Yaowu Zhi records a local folk single remedy: take 30–60g of Xueyao decocted in water to treat cough and hemoptysis. This type of cough and hemoptysis is usually accompanied by lung-heat symptoms such as dry mouth and tongue.Xueyao combined with Xiakucao (Prunella) treats lymph-node enlargement (scrofula). Hubei Zhongcaoyao Zhi records that one may take 30g of Xueyao and 1500g of Xiakucao, boil with an appropriate amount of honey into a paste, to treat lymph-node enlargement. In this formula Xueyao serves as an adjuvant; the main herb is Xiakucao. Xiakucao can be used to treat lymphoma, scrofula (tuberculous lymphadenitis), or lymph-node enlargement caused by various inflammations.A close relative of Xueyao, the Urticaceae plant Huadiancao (also called Youyoucao), is similar in shape and effect to Xueyao, and the two are often confused. The whole herb of Youyoucao decocted internally also has the effects of stopping cough and bleeding, reducing swelling and relieving pain, and treating scrofula. Youyoucao is a common herb for treating cough, hemoptysis, and steaming fever of pulmonary tuberculosis.