Source 出处 · Xiaoer Yao Zheng Zhi Jue · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Qian Yi's Xiaoer Yao Zheng Zhi Jue is generally regarded as the earliest extant systematic pediatric monograph in the Chinese tradition, and it reached its surviving form through the editing of his student Yan Xiaozhong rather than Qian Yi's own hand. This formula is one of the shortest things in it, and the name is worth unpacking: in the five-phase correspondences the lung belongs to metal and its colour is white, so draining the white means draining the lung. What it drains is described as latent fire, and that word does real work. It is not written for someone who has just caught a cold. It is written for a heat that has settled in and stayed.
The composition states the quiet part out loud. Two root barks, both gentle by the standards of heat-clearing materia medica, plus liquorice and rice. There is no gypsum here, no scutellaria, no coptis. A pediatric author writing for small children built his lung-heat formula out of the mildest materials available and then added cooking rice to it, which is not decoration: rice is there to acknowledge that protecting the stomach matters more in a sick child than clearing heat quickly.
Then the part this knowledge base insists on saying first. The presentation the formula addresses - cough, rapid or laboured breathing, fever that runs toward afternoon - is precisely the presentation in which modern pediatrics is least willing to wait. In an infant or small child those signs cover pneumonia, bronchiolitis, croup, asthma, pertussis, foreign body aspiration and cardiac causes, and several of them deteriorate over hours rather than days. Indrawing of the chest wall between or below the ribs, grunting, flaring of the nostrils, pauses in breathing, blue or grey lips, unusual sleepiness or refusal to feed move the timetable from watching to emergency immediately. Fever in a young infant belongs in front of a doctor the same day. A cough lasting more than a few weeks, or one with weight loss, night sweats or blood, needs investigation for tuberculosis, pertussis, asthma and retained foreign body before it needs a pattern diagnosis. That is not an argument against the formula. It is an argument about order.
On the individual materials: lycium root bark comes from a Solanaceae plant, the same family as goji berry, and the interaction reports that exist - including the warfarin case reports - concern the fruit; whether the root bark shares them is not something this entry can state. Mulberry root bark should not be confused with mulberry leaf, mulberry twig or mulberry mistletoe, which are separate materia medica with separate names; it is frequently dispensed honey-fried, and raw and honey-fried are not interchangeable. Liquorice carries the glycyrrhizin problem in full: sustained generous intake produces a mineralocorticoid-type picture with fluid retention, raised blood pressure and low potassium, and that hazard is real in children as well as adults. Finally, nothing here is strongly toxic - which is exactly why it gets used at home, and worth remembering that gentle describes the herbs, not the diagnosis.
钱乙的《小儿药证直诀》通常被认为是中国传统医学里现存最早的系统儿科专著，而它传世的形态出于其弟子阎孝忠的整理，并非钱乙亲手定稿。此方是全书中最简短的方子之一，而方名值得拆开讲：在五行对应中肺属金、其色为白，故「泻白」即泻肺。所泻者，书中称「伏火」——这个词不是虚设的闲笔。此方不是为刚受寒的人而设，而是为一团已经安顿下来、不再离去的热而设。
组成把没说出口的那句说了出来：两味根皮，按清热药的标准都属平和，再加甘草与粳米。方中没有石膏，没有黄芩，没有黄连。一位为小儿立论的医家，用他能找到的最温和的材料组成了这张清肺方，还往里加了一把做饭的米——这不是点缀，而是在声明：对一个生病的孩子来说，顾护胃气比快速清热更要紧。
接下来是本站坚持要放在最前面的部分。此方所对应的表现——咳嗽、气急或喘息、午后身热——恰恰是现代儿科最不肯等待的那类表现。在婴幼儿身上，这些表现覆盖肺炎、毛细支气管炎、哮吼、哮喘、百日咳、异物吸入以及心脏原因，其中几种的恶化以小时计而非以日计。胸骨上窝、肋间隙或剑突下在吸气时凹陷、呻吟、鼻翼扇动、呼吸暂停、口唇发青或发灰、异常嗜睡或拒奶，会把时程立刻从「观察」推进到「急症」。小婴儿发热，应当当天就诊。咳嗽超过数周，或伴体重下降、盗汗、咯血者，需要先排查结核、百日咳、哮喘与气道异物，而不是先辨证。这些都不是不用此方的理由，而是关于次序的理由。
单味药：地骨皮来源于茄科植物，与枸杞子同科，而现有相互作用的报告——包括那些与华法林相关的个案报告——是针对果实而言的；根皮是否同样如此，本条不能断言。桑白皮不可与桑叶、桑枝、桑寄生相混，那是各自有名、各为一物的药材；它常以蜜炙品入药，生品与炙品不可互代。甘草的问题在甘草酸：长期较大量的摄入会造成类似盐皮质激素过多的表现——水钠潴留、血压升高、低钾——而在儿童身上同样成立。最后一点：这里没有一味猛毒之品，这正是它进了家庭药箱的原因；而「平和」说的是药，不是那个诊断。