Source 出处 · Xiaoer Yao Zheng Zhi Jue · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Xie Huang San is recorded in Xiaoer Yao Zheng Zhi Jue, Qian Yi's eleventh-century book, one of the earliest Chinese works devoted to children. Five ingredients: agastache or patchouli leaf, gardenia fruit, gypsum, licorice root and saposhnikovia root. The classical text directs that the ingredients be stir-fried with honey and wine before being ground to a powder. That is a processing instruction in the source, not a serving instruction, and the alcohol is driven off in the pan; it is still worth knowing if anything of the kind is being prepared at home in a household with children. The same note carries a rule that has nothing to do with this formula and everything to do with honey: honey should never be given to an infant under twelve months, because of infant botulism.
The ingredient that makes this formula worth reading is the last one. A powder named for draining fire that contains a warm, acrid, upward and outward herb looks like a contradiction until you read it in the tradition's own terms. The reasoning is that fire which is pent up should be vented rather than merely doused: give the trapped heat a way out instead of only pouring cold on it. Whether that reasoning maps onto anything measurable is not something this library claims to know. What it does say is that the shape of the argument is visible right there in the ingredient list, and being able to see a two-thousand-year-old argument in five herbs is most of the reason to read a formula at all.
The name does the same work. Yellow is the colour the tradition assigns to earth, and to the spleen and stomach; the formula drains the spleen. Its companion, Xie Qing Wan, drains the liver, green being the colour of wood. Colour as organ name is one of the more surprising things in this corpus for an English-language reader, and it is worth learning once.
What the source aims it at is mouth sores, bad breath, thirst and irritability, and in children a repetitive poking of the tongue. Each of those deserves a modern sentence.
Bad breath is mostly oral, and mostly not a mystery: periodontal disease, coating on the tongue, tonsil stones, chronic sinusitis with postnasal drip, and reflux. Less commonly it is metabolic, and diabetic ketoacidosis, renal failure and hepatic failure each have their own characteristic smell. Helicobacter pylori has been proposed as a cause and the association is not settled.
Mouth ulcers are usually ordinary aphthous ulcers, which are miserable and harmless and heal by themselves. Recurrent ones have a short but real differential: deficiency of iron, folate, vitamin B12 or zinc; coeliac disease; inflammatory bowel disease; Behçet's disease; and drug-induced ulceration from NSAIDs, beta-blockers, methotrexate and nicorandil. And there is one threshold that matters more than the list: a mouth ulcer that has not healed after three weeks should be seen. That is the referral threshold used in most guidelines for possible oral cancer. In the great majority of cases it is not that, and the threshold exists precisely because the ones that are look exactly like the ones that are not.
Repetitive tongue movement in a child is read in the classical text as stomach heat. Today it sits within a differential that includes tics, stereotypies, orofacial dystonia and drug-induced reactions, metoclopramide and antipsychotics among them. This library does not adjudicate between those, but a parent should know that it is not a matter that a single word like heat closes.
For the herbs themselves: gardenia fruit contains geniposide, and high-dose animal studies have raised liver concerns while human evidence remains limited, which is exactly how this library will state it. Gypsum is a mineral. Licorice carries the pseudoaldosteronism risk of low potassium, raised blood pressure and oedema with prolonged use, worse alongside diuretics, digoxin or corticosteroids. The aromatic leaf is one of the places where names mislead: the agastache used in the north and the patchouli used in the south are two different plants listed separately in the pharmacopoeia, and products should say which is in them. Saposhnikovia is largely wild-collected and has been under collection pressure.
This library does not claim that this formula freshens breath, heals ulcers or treats any disease.
泻黄散著录于钱乙《小儿药证直诀》—— 我国现存较早的儿科专书之一。五味：藿香叶、栀子、石膏、甘草、防风。原文要求诸药以蜜酒拌炒后为散。这是文献里的**炮制**要求，不是服法，酒在锅中已挥发；但家中有小儿且自行处置时，这句话值得知道。同一条提醒还带出一条与本方无关、却与蜂蜜有关的规则：一岁以下婴儿不应摄入蜂蜜，因婴儿肉毒中毒之故。
让这首方值得一读的是最后一味。一首名为「泻火」的散剂里含一味辛温上行外散之药，看起来自相矛盾，直到你把它放回传统自己的语境里读：其论证是「火郁发之」—— 郁住的热应当给它出路，而不只是一味以寒浇之。这个论证是否对应任何可测量的东西，本库不声称知道；本库能说的是，论证的形状就摆在五味药里，而能从五味药中看出来一场两千年前的论证，正是读方的意义所在。
方名做的是同一件事：黄是传统配给土、配给脾胃的颜色，泻黄即泻脾；它的同伴泻青丸泻肝，青为木之色。以颜色作脏腑名，对英语读者是这套文献里比较意外的一件事，值得学一次。
原文所对的是口疮、口臭、烦渴易怒，以及小儿弄舌。这几项今天各自都值得一句话。
口臭多数来自口腔，也多数不难解：牙周病、舌苔、扁桃体结石、慢性鼻窦炎所致的鼻后滴漏、胃食管反流；较少见的是代谢性的 —— 糖尿病酮症酸中毒、肾功能衰竭与肝功能衰竭各有其气味特征。幽门螺杆菌曾被提出为原因之一，关联未定。
口腔溃疡多数是普通的复发性阿弗他溃疡，很难受但无害，会自行愈合。反复发作则有一份不长却真实的鉴别：铁、叶酸、维生素 B12 或锌缺乏；乳糜泻；炎症性肠病；白塞病；以及 NSAIDs、β受体阻滞剂、甲氨蝶呤与尼可地尔所致的药物性溃疡。比这份清单更要紧的是一条阈值：**超过三周不愈的口腔溃疡应当就诊** —— 这是多数指南用于排除口腔癌的转诊阈值。绝大多数最后都不是，而这条阈值之所以存在，正因为是的那一些看起来和不是的那一些一模一样。
小儿反复弄舌，在古典文本里读作脾胃有热。今天它落在抽动、刻板动作、口面部肌张力障碍与药物反应（甲氧氯普胺与抗精神病药在内）这一组鉴别之中。本库不替读者裁决，但家长应当知道：这不是「火」一个字可以收尾的事。
几味药自己：栀子含栀子苷，**高剂量动物实验曾提出肝脏方面的关注，而人体证据有限** —— 本库就是这样写的；石膏是矿物；甘草长期用有甘草酸假性醛固酮增多症之虑（低钾、血压升高、水肿），与利尿剂、地高辛或糖皮质激素同用时更明显；芳香那一味正是名字容易骗人的地方 —— 北方所用的藿香与南方所用的广藿香在药典里是分列的两物，产品应当写明是哪一种；防风主要依赖野生采挖，长期存在采挖压力。
本库不声称本方能消除口臭、愈合溃疡或治疗任何疾病。