Tao Hua Tang (Peach Blossom Decoction) táo huā tāng · 桃花汤

Safety. Three ingredients: 赤石脂 (halloysite, a red clay mineral), 干姜 (dried ginger rhizome), and 粳米 (polished non-glutinous rice). Quantities, preparation and method of taking are deliberately not listed here. The line is blunt — 下利便脓血者，桃花汤主之 — for diarrhoea with pus and blood in the stool, this formula governs. This library’s position on blood in the stool is one sentence and it does not bend: **it offers no plan for bleeding**. Not a modified plan, not a gentle one. Blood and pus in the stool in the present day carries a differential that includes inflammatory bowel disease, infectious colitis (Shigella, Campylobacter, Clostridioides difficile among them), ischaemic colitis, and colorectal cancer — and that list is separated by examination, endoscopy and microbiology, not by pattern differentiation. A reader who arrives at this page because they have blood in their stool has arrived at a page about a text from the Han dynasty, and the most useful thing that page can do is say so and step aside. 赤石脂 is why the entry is worth writing anyway: it is one of the very few mineral drugs in this library, and two things follow from that. The first is the impurity question a plant does not carry to the same degree — heavy metals, arsenic and lead in mineral traditional medicines are documented often enough that several pharmacopoeias set limits for them. This library records that such limits exist; it does not pretend to quantify any particular sample. The second is adsorption: clay minerals bind whatever they are mixed with. An adsorbent taken by mouth will bind other medicines taken alongside it and reduce their absorption — the same reason ordinary kaolin-type products carry a separation interval in their labelling. 干姜 is dried ginger: not the fresh 生姜 of the kitchen, and not treated as interchangeable with it in classical thinking. 粳米 is rice — a real carbohydrate load, and a known dietary source of inorganic arsenic, which is why several regulators set limits specifically for rice-based foods for infants and young children. The classical texts also direct a divided use of 赤石脂 in this formula, part decocted and part taken as powder; this library notes that the direction exists and does not reproduce the preparation. Chinese-language clinical literature on 桃花汤 in chronic diarrhoea and in colitis pictures exists and is small and methodologically limited. Recorded as existing; not recorded as established.