Source 出处 · Shanghan Lun · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Fourteen ingredients, and the source line says 为难治 — difficult to treat. A corpus that usually writes as though it knows what to do stops here and says so. That admission is the most useful sentence in the entry, and it is the one that gets deleted when people quote the formula.
The setting, again, is after treatment: 伤寒六七日，大下后 — after drastic purging. What follows is a picture of someone unwell in several systems at once. 寸脉沉而迟, a deep slow pulse at the wrist; 手足厥逆, cold hands and feet; 下部脉不至, the pulse at the ankle cannot be felt; 咽喉不利, the throat obstructed; 唾脓血, spitting pus and blood; 泄利不止, diarrhoea that will not stop.
Read that as a modern reader and it reads like a person in trouble. Cold extremities with an impalpable distal pulse is a description of failing peripheral perfusion: septic, hypovolaemic or cardiogenic shock, acute limb ischaemia, aortic dissection, severe hypothermia, profound dehydration. Acute limb ischaemia is a vascular surgical emergency measured in hours — the limb is salvageable for roughly six. It is not a pulse that a decoction should be expected to bring back.
唾脓血, pus and blood in what is brought up, is imaging today. Lung abscess, bronchiectasis, tuberculosis, necrotising pneumonia, lung cancer, pulmonary infarction, invasive fungal infection, granulomatosis with polyangiitis, and bronchopleural or oesophago-airway fistula are the list, and the first investigation is a chest X-ray or CT rather than a formula. 咽喉不利 with any difficulty breathing or swallowing is an airway assessment: epiglottitis, retropharyngeal abscess, Ludwig's angina and deep neck infection can close an airway quickly. 泄利不止 means fluid and electrolyte loss and a search for the cause — Clostridioides difficile, invasive bacterial enteritis, uraemia, thyrotoxicosis, medication.
The formula is led by 麻黄, ephedra, and this is where the safety note has to be blunt. Ephedra contains ephedrine and pseudoephedrine, sympathomimetic amines that raise blood pressure and heart rate, cause insomnia, tremor and urinary retention, and are hazardous where there is angina, poorly controlled hypertension, hyperthyroidism, prostatic enlargement or narrow-angle glaucoma. They stack with caffeine, stimulants, decongestants and monoamine-oxidase inhibitors. The United States banned ephedra-containing dietary supplements in 2004; in China the plant is controlled as a precursor for methamphetamine manufacture; ephedrine remains on the World Anti-Doping Agency prohibited list. That the leading herb is a pressor amine, in a formula whose indication includes cold extremities and an unfelt distal pulse, is a contradiction worth stating plainly. Raising the blood pressure is not the same as restoring perfusion, and something that makes the numbers look better while a limb is ischaemic has made the situation harder to read, not easier.
The rest of the fourteen: 石膏 is hydrated calcium sulphate, a mineral product, and mineral products carry the question of heavy metal impurity; it is not 滑石, which carries the asbestos association. 升麻 is Cimicifuga; black cohosh, Cimicifuga racemosa, has a substantial record of liver injury reports, and while the Chinese materia medica species are related rather than identical, this entry does not treat them as equivalent. 天门冬 is asparagus tuber, not the ornamental asparagus fern that is a common houseplant and a common poisoning call. 萎蕤 is Polygonatum odoratum. 当归 contains furanocoumarins with photosensitivity, and there are case reports of it raising INR in people on warfarin. 白术 is Asteraceae, which matters to anyone allergic to ragweed or chrysanthemum. 知母 has preclinical hypoglycaemic signals; that is a reason for caution, not a reason to combine it with glucose-lowering medicine. 茯苓 is a fungal sclerotium, not 土茯苓. 甘草 carries glycyrrhizin. 桂枝 carries cassia coumarin. 芍药 is the white-versus-red ambiguity. 干姜 is dried ginger, not galangal. 黄芩 is the skullcap identification problem again.
Fourteen herbs means fourteen sets of unknowns, and the text that recorded this formula had the honesty to call it 难治 first.
十四味，条文自己写着「为难治」。一部通常写得像知道该怎么办的书，到这里停住说明白：这不好治。这句自白是整条里最有用的一句，也是人们引用这首方时最常被删掉的一句。
背景又一次是治疗之后：「伤寒六七日，大下后」。此后出现的是一个人同时多处出问题的画面 —— 寸脉沉而迟、手足厥逆、下部脉不至、咽喉不利、唾脓血、泄利不止。
用今天的眼光读，这是一个情况不好的人。**四肢冷加上摸不到的足部脉搏，就是外周灌注衰竭的描述**：脓毒性、低血容量性或心源性休克，急性肢体缺血，主动脉夹层，重度低体温，或严重脱水。急性肢体缺血是按小时计的血管外科急症 —— 肢体可挽救的窗口大约六小时。这个脉搏不该指望一碗汤药把它带回来。
「唾脓血」今天就是影像：肺脓肿、支气管扩张、结核、坏死性肺炎、肺癌、肺梗死、侵袭性真菌感染、肉芽肿性多血管炎、支气管胸膜瘘或食管气道瘘 —— 第一项检查是胸片或 CT，不是方子。「咽喉不利」一旦合并呼吸或吞咽困难，就是气道评估：会厌炎、咽后脓肿、Ludwig 咽峡炎与颈部深部感染可以在很短时间内封闭气道。「泄利不止」意味着水电解质丢失与找病因：艰难拟梭菌、侵袭性细菌性肠炎、尿毒症、甲亢、药物。
这首方以麻黄为首，而安全提示必须说得直接：**麻黄含麻黄碱与伪麻黄碱，是拟交感胺** —— 升压、加快心率、失眠、震颤、尿潴留；心绞痛、血压控制不佳、甲亢、前列腺增生与闭角型青光眼均为危险情形；与咖啡因、兴奋剂、减充血剂和单胺氧化酶抑制剂叠加。美国 2004 年起禁售含麻黄的膳食补充剂；中国将麻黄类按甲基苯丙胺前体管制；麻黄碱仍在世界反兴奋剂机构禁用清单内。**以一味升压的拟交感胺为君，而所治之人「手足厥逆、下部脉不至」—— 这个矛盾值得明写：升高血压不等于恢复灌注；一种让数字变好看而肢体仍在缺血的东西，是让局面更难判断，不是更容易。**
其余十三味：石膏是含水硫酸钙的矿物药，矿物药就有重金属杂质这一问，且它**不是滑石**（滑石有石棉伴生问题）。升麻是 Cimicifuga 属；**黑升麻（Cimicifuga racemosa）有大量肝损伤报告**，中药所用为同属近缘种而非同种植株，本条目不主张等同。天门冬是天门冬的块根，**不是**作为观赏植物的文竹／天门冬属绿植（常见误食中毒）。萎蕤即玉竹（Polygonatum odoratum）。当归含呋喃香豆素（光敏），并有与华法林合用升高 INR 的病例报告。白术属菊科 —— 对豚草或菊花过敏者这一项要紧。知母有降血糖的临床前信号；**那不是与降糖药同用的理由，是需要谨慎的理由**。茯苓是真菌菌核，**不是土茯苓**。甘草是甘草酸问题；桂枝是桂皮香豆素；芍药是白芍赤芍之别；干姜不是高良姜；黄芩又是黄芩属误判。
十四味药就是十四组未知，而记录这首方的那段文字，先把「难治」两个字写在了前面。