Qiang Huo Sheng Shi Tang (Notopterygium Dampness-Overcoming Decoction) qiāng huó shèng shī tāng · 羌活胜湿汤

Safety. Qiang Huo Sheng Shi Tang is recorded in Neiwaishang Bianhuo Lun, Li Gao's thirteenth-century discussion of how internal damage and external contraction are to be told apart. Its name states the strategy outright: qiang huo is the chief herb, and overcoming dampness is the aim. Seven herbs, almost all pungent and warm, almost all moving upward and outward. The reasoning is that when wind-damp lodges in the exterior, the way out is the way it came in. Two features make it worth reading rather than only cataloguing. The first is the pairing of qiang huo and du huo: qiang huo is classically assigned to the upper body and the taiyang channel, du huo to the lower body and the shaoyin, so a single pair is read as covering the whole body-axis in one gesture. The second is what the formula does not contain. There is not one herb here that drains dampness through urination. It resolves damp by dispersing it, which is exactly why classical commentary restricts it to damp in the exterior and sends the reader to other formulas once water has collected internally. The modern reader should notice what painful obstruction can mean today. Shoulder or upper-back pain that radiates, or that comes with chest tightness, breathlessness, sweating or nausea, belongs on the emergency pathway first: acute coronary syndrome, aortic dissection and pulmonary embolism all present this way, and the classical text has no instrument for separating them from wind-damp. Neck and upper-back pain with numbness, clumsiness of the hands, gait disturbance, or any change in bladder and bowel control suggests cervical myelopathy. A new severe headache with neck stiffness, fever or altered consciousness, or one that reaches maximum intensity in seconds, is a different category altogether and is not a matter for pattern differentiation. On safety: most of the composition is pungent, warm and drying, so this is not a formula for long daily use, and the traditional cautions frame it as unsuitable where there is yin depletion or existing fluid exhaustion. Chuan xiong is used to move blood and is treated with caution alongside anticoagulant and antiplatelet drugs, and in pregnancy. Qiang huo, du huo, gao ben and fang feng are all umbellifers, a family associated with furanocoumarin photosensitivity; the family-level association is established, the risk from this particular formula is not. Zhi gan cao, honey-fried licorice, carries the well-described pseudoaldosteronism syndrome of sodium and water retention, potassium loss and rising blood pressure when taken persistently — worth naming in a formula whose stated purpose is to disperse retained fluid. Gao ben is not interchangeable with other ligusticum species that circulate under similar names. This entry makes no claim that the formula treats any named disease.