Baiye Tang (Arborvitae Leaf Decoction) bǎi yè tāng · 柏叶汤

Safety. Jingui Yaolüe records Baiye Tang in its chapter on palpitations, blood ejection, blood in the stool and blood stasis, for one indication: 吐血不止者 — blood being brought up that does not stop. Three herbs are listed, together with the vehicle called 马通汁. This library does not reproduce that vehicle, does not suggest a substitute for it, and says plainly that no modern reference describes a safe way to prepare it. Two honest statements come before anything else about this formula. The first is that 吐血不止 describes an emergency in any century. Vomiting blood is upper gastrointestinal bleeding until shown otherwise: peptic ulcer disease, oesophageal varices from portal hypertension, a Mallory-Weiss tear, erosive gastritis from non-steroidal anti-inflammatory drugs or alcohol, malignancy, Dieulafoy lesion. It has to be separated from swallowed blood after a nosebleed and from haemoptysis, which comes from the lung rather than the gut. The procedure is endoscopy, and it is at once diagnostic and therapeutic. Even with modern intensive care, variceal bleeding carries substantial short-term mortality. The single most useful question today is whether the person is taking an anticoagulant or an antiplatelet drug. This entry records what a second-century text said; it is not a route to managing bleeding, and no sentence in it delays emergency care. The second honest point is about the arborvitae leaf itself. Later practice generally uses it charred, as 侧柏炭, for bleeding presentations, while the classical line says only 柏叶. That divergence is a historical fact about how the tradition developed. It is not evidence that charring changes outcomes, and this library makes no such claim. What the leaf does contain is measurable thujone, a monoterpene whose GABA-antagonist action can provoke seizures when exposure is high enough. Of the other two ingredients: mugwort leaf is a common cause of contact dermatitis in people sensitised to Asteraceae, and Artemisia pollen is among the dominant autumn allergens across northern China; its volatile oil includes camphor, 1,8-cineole and thujone, and cases of liver injury have been reported. Dried ginger is comparatively innocuous but shows weak antiplatelet activity in vitro, which is worth knowing next to an indication for bleeding that will not stop. This library holds no approach, herb or otherwise, for stopping bleeding. That sentence is the one that matters most here.