Source 出处 · Taiping Huimin Hejiju Fang · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Xiang Ru San is recorded in the Taiping Huimin Hejiju Fang, the Song-dynasty official formulary, and it has three ingredients. It is the formula a reader is most likely to misunderstand, because the category it belongs to is named after summer heat while the state it is recorded for is, in modern terms, a summer cold.
The classical picture is this: in the hottest part of the year a person sleeps in the open, sits in a draught, bathes in cold water, or drinks iced things to excess — and then develops aversion to cold, fever, no sweating, a head that feels bound, aching limbs, and abdominal pain with vomiting and loose stool. Classical authors separated this from what they called yang summerheat and gave it the name yin summerheat. The distinction is not academic: one is exposure to heat, the other is exposure to cold during hot weather. Later texts called this herb the ephedra of summer, and that single phrase says what the formula does — it promotes sweating. It is the wrong direction for a person who is overheating, and the classical tradition knew that, which is why it placed the formula on the cold side of the pair.
That matters because the modern reader who arrives here is most likely looking for something to give someone who has collapsed in the heat. Heat stroke is a different event entirely. It is a core body temperature above 40°C with disturbed brain function — confusion, strange behaviour, loss of consciousness, seizures — and it kills or causes permanent organ damage within hours. The window is measured in minutes, and the treatment is rapid cooling, ideally cold-water immersion, with emergency transport started at the same time. Sweating induction has no part in it. Anyone with hot skin and altered mental state in the heat is on an emergency pathway, and this page is not on that pathway.
The second thing worth being plain about is the vomiting and diarrhoea. In an emergency department, abdominal pain with vomiting and diarrhoea in summer is worked through as a differential: acute appendicitis, food poisoning, bacterial or viral gastroenteritis, and in the right setting cholera and dysentery. Rehydration is the treatment that matters. Blood in the stool, high fever, signs of dehydration, or any change in consciousness turn this into an emergency. Classical texts paired this formula with rest and thin gruel afterwards; they did not send the person back out into the heat.
The three ingredients each carry a real note. The herb's volatile oil is dominated by phenolic compounds of the carvacrol and thymol type, which are irritant to skin and mucous membranes. The lablab bean in its raw state contains saponins, lectins and trypsin-inhibitor type antinutritional factors, and eating it uncooked can cause nausea, vomiting and diarrhoea — which is precisely why the classical text specifies that it be lightly dry-fried. Magnolia bark is the bark of a Magnolia species; magnolol and honokiol have sedative and muscle-relaxant effects in animal studies, so an additive effect with sedative medication is at least plausible, and wild magnolia is a protected resource in China with commercial supply coming from cultivation. This library does not endorse wild-sourced material.
This page is not a recommendation. It records that the formula exists in the literature. No quantity, no preparation, no regimen, and no claim that it helps anything. Pregnancy, breastfeeding, children, older adults, impaired liver or kidney function, and any sedative, diuretic, antihypertensive or anticoagulant medicine taken on medical advice each remove what room there was. If a preparation like this has been taken and there is persistent vomiting, abdominal pain that is localising, tremor, confusion, or reduced urine output, treat it as an emergency and bring the packaging.
香薷散著录于《太平惠民和剂局方》，全方三味。它是本库最容易被误读的一首 —— 因为它所属的类别以「暑」为名，而它所对应的情形，用今天的话说，是**夏天的一场感冒**。
古典的画面是这样：一年中最热的时候，人露天而卧、当风而坐、冷水洗浴、或过食冰冷，随后恶寒发热、无汗、头重如裹、肢体酸痛、腹痛吐泻。古典作者把它与「阳暑」分开，命名为「阴暑」。这个区分不是文字游戏：一种是受热，一种是在热天里受寒。后世把香薷称作「夏月麻黄」，这一句话就说明了这首方在做什么 —— 它发汗。对一个正在体温失控的人来说，方向是反的；而古典传统对此是清楚的，所以它把这首方放在了这一对里属寒的那一侧。
这一点要写清楚，因为读到这里的现代读者，多半是在找「有人热倒了该给什么」。热射病完全是另一件事：核心体温超过 40℃ 并伴中枢功能异常 —— 意识改变、行为异常、昏迷、抽搐 —— 在数小时内致死或造成永久器官损伤。时间窗以分钟计，处理是快速降温（最好是冷水浸泡），同时启动转运。发汗不在其中。皮肤灼热伴意识改变的人走的是急救路径，本页不在这条路径上。
第二件要直说的是吐泻。在急诊里，夏季的腹痛伴吐泻是要逐一鉴别的：急性阑尾炎、食物中毒、细菌性或病毒性胃肠炎，在特定地区还有霍乱与痢疾。真正要紧的处理是补液。血便、高热、脱水征象、或任何意识改变，都使它转为急症。古典文献在这首方之后给的是休息与糜粥自养，而不是让人回到日头底下。
三味药各自都有一条实在的注脚。香薷的挥发油以香荆芥酚（carvacrol）与百里香酚（thymol）一类酚性成分为主，这类成分对皮肤与黏膜有刺激性。白扁豆生品含皂苷、凝集素与胰蛋白酶抑制剂等抗营养因子，生食可致恶心、呕吐与腹泻 —— 这正是原方注明「微炒」的原因。厚朴是木兰属树皮，和厚朴酚与厚朴酚在动物实验中显示镇静与肌松作用，与镇静类药物叠加至少是可能的；野生厚朴在国内属受保护资源，商品以栽培为主，本库不主张使用野生来源。
本页不是建议。本库记录的是文献中有此方：不列用量、不列制法、不列服法，也不主张它对任何情况有益。妊娠、哺乳、儿童、老年、肝肾功能受损，以及正在使用镇静／利尿／降压／抗凝类处方药，任何一项都足以抹去残余的空间。若已服用此类制剂并出现持续呕吐、逐渐固定的腹痛、震颤、意识改变或尿少，属急症：立即就医，并把原包装带上。