Simiao Yong'an Tang: A Famous TCM Formula for Vascular Disease

Simiao Yong'an Tang is a well-known formula in TCM external medicine. The name of the formula first appears in "Yan Fang Xin Bian" (New Compilation of Proven Prescriptions), compiled by the Qing-dynasty physician Bao Xiang'ao, but this prescription was not first recorded there. In the book "Research and Practice of Simiao Yong'an Tang in Preventing and Treating Cardiovascular and Cerebrovascular Diseases," compiled by contemporary scholar Zhang Junping and others, the authors point out that this formula first appeared in "Hua Tuo Shen Yi Mi Zhuan" (the true author and date of which are unknown), and was also included in "Shishi Milu" (Secret Records of the Stone Chamber) by the famous Qing physician Chen Shiduo.

Simiao Yong'an Tang is a famous formula for treating "heat-toxin type gut-rot" (duju) in external medicine. Duju is a TCM disease name. The disease begins with cold and numb limbs, and in later stages the toe joints become necrotic and fall off, turning black, decaying and ulcerating, with ulcers that do not heal for a long time. This corresponds to modern vasculitis and vascular thrombosis—equivalent to thromboangiitis obliterans and atherosclerotic occlusive disease, whose causes are all vascular lesions. The disease progresses slowly with a long course, often worsens in cold seasons, and may recur after cure.

Yanghe Tang is mainly used to treat yin-type gut-rot, while Simiao Yong'an Tang is the main formula for heat-toxin-type gut-rot. Common symptoms of heat-toxin-type gut-rot include slight swelling and burning heat of the affected limb, severe pain, ulceration and fetid decay, and in severe cases successive shedding of toe joints extending to the dorsum of the foot; the patient is feverish and irritable, thirsty, with a red tongue and rapid pulse.

Patients after chemotherapy and targeted therapy often present with "gut-rot" symptoms; the author once saw a lung adenocarcinoma patient whose toes had almost completely fallen off after chemotherapy. Chemotherapy and targeted drugs easily damage patients' blood vessels, so in oncology departments Simiao Yong'an Tang is a commonly used prescription. Simiao Yong'an Tang can be used not only to treat the aftereffects of chemotherapy and targeted drugs, but also as a decoction-based formula for solid tumors of heat-toxin type.

Simiao Yong'an Tang is also commonly used to treat erysipelas, sciatica, rheumatoid arthritis, carpal tunnel syndrome, ankylosing spondylitis, intractable gout, and retinal vein occlusion—diseases whose patterns belong to internal accumulation of heat-toxin with stasis obstructing the channels. The key to pattern differentiation is whether the patient has the series of symptoms of exuberant heat-toxin.

Simiao Yong'an Tang consists of four herbs: Xuanshen (Scrophulariae), Jinyinhua (Lonicerae), Danggui (Angelicae) and Gancao (Glycyrrhizae). The prescription recorded in "Shishi Milu" is: 3 liang of Jinyinhua, 3 liang of Xuanshen, 2 liang of Danggui, 1 liang of Gancao, decocted in water. In the formula, Jinyinhua and raw Gancao clear heat and resolve toxin; Xuanshen cools blood and reduces swelling; Danggui activates blood and resolves stasis while also nourishing blood; Gancao also strengthens the spleen. The four herbs used together jointly produce the effects of clearing heat, resolving toxin, reducing swelling and relieving pain.

"Shishi Milu" is an early Qing work; at that time one liang was approximately 17 g. Converted to modern dosage, this is approximately: Jinyinhua 50 g, Xuanshen 50 g, Danggui 35 g, raw Gancao 15 g. However, the commonly used clinical dosage is Jinyinhua 30 g, Xuanshen 30 g, Danggui 20 g, raw Gancao 10 g. Jinyinhua does not tolerate prolonged decoction and should be added later.

In clinical application, this formula may be modified according to the patient's specific condition. If heat-toxin is severe with obvious swelling of the affected area, dark-red or bright-red skin, and burning pain, blood-cooling herbs such as Danshen, Mudanpi, Chishao and Zicao may be added. If blood stasis and qi stagnation cause severe pain, Huoxiang, Moyao, Xuejie, Yuanhu and Xiangfu may be added to activate blood, regulate qi and stop pain. If heat-toxin damages yin with burning heat, vexing thirst and dry skin, Mudanpi, Shengdi, Maidong and Shihu may be appropriately added to clear heat and nourish yin. If the local skin has already ulcerated, the wound flesh is not fresh and the odor is offensive, Fangji, Cangzhu, Huangbai, Zexie, Yiyiren, Baiji and Sheng Huangqi may be added to clear heat, drain dampness, and astringe and close the sore. If the disease is in the upper limbs, Jianghuang, Qianghuo and Sangzhi may be added; if in the lower limbs, Niuxi, Mugua and Yiyiren may be added.