Source 出处 · Jingui Yaolüe · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. The name of this formula is the biggest single source of misunderstanding around it. 肾着 means cold-damp fixed at the kidney region - 着 is to settle, to stick - and in classical usage it does not mean disease of the kidney organ. Jingui Yaolüe says so explicitly, by listing what is not wrong: 小便自利, urination is normal; 饮食如故, appetite is as it was; 反不渴, and notably not thirsty. Those three negative findings are the argument. A person with kidney disease and fluid retention would not be described this way, and neither would a person with the thirst and polyuria of uncontrolled diabetes. The classical text is detaching the complaint from the organ whose name it borrows. A reader who sees 肾 on the label and concludes they have kidney disease has done the opposite of what the text did.
What remains is a picture worth reading closely: 身体重, the body heavy; 腰中冷, 如坐水中, the waist cold as if sitting in water; and the line everyone remembers, 腹重如带五千钱, heaviness in the abdomen as though carrying five thousand coins. Low back pain with heaviness is, today, a differential and not a diagnosis. It includes mechanical and degenerative causes, which are the common ones and the benign ones. It also includes vertebral compression fracture, spinal infection such as discitis and epidural abscess, metastatic malignancy, myeloma, aortic aneurysm and dissection - the latter classically presenting as tearing pain and measured in hours - renal colic, pyelonephritis, pancreatitis radiating to the back, and cauda equina syndrome.
The red flags are the reason that list exists, and they are worth stating plainly: new incontinence or retention of urine or stool, numbness in the saddle area, progressive leg weakness, fever, pain that wakes a person at night, unexplained weight loss, a history of cancer, long-term corticosteroid use, injecting drug use, significant trauma, and any new back pain above the age of fifty. Cauda equina syndrome is a surgical emergency, and it announces itself through bladder and bowel change rather than through the severity of the pain.
The classical aetiology deserves to be kept: 身劳汗出，衣里冷湿，久久得之 - labour that brings sweat, then cold damp clothing held against the body, over a long time. It is an occupational and environmental observation, and more specific than most classical aetiologies.
On the materials. Licorice carries the glycyrrhizin problem: a mineralocorticoid-type pattern of sodium retention with potassium loss, and the risk is greatest when it is combined with potassium-losing diuretics, digoxin or anthraquinone laxatives. Poria (茯苓) is a fungal sclerotium and is not 土茯苓, Smilax glabra - a different substance with a deceptively similar name. Dried ginger is a concentrated spice material. Atractylodes is a rhizome in the Asteraceae, and contact dermatitis from the family is common. The name 肾着汤 is applied to more than one composition in the later literature; this library records the four-ingredient Jingui Yaolüe version and makes no judgement between variants. There are no adequate safety data for pregnancy or breastfeeding. Chinese clinical reports on this formula for low back pain are small and mostly uncontrolled; this library records that the research exists, not that benefit has been established.
方名是这首方最大的误会来源。「肾着」的「着」是附着、停留，指寒湿停留在腰部，在古典用法里**不是肾脏本身的病**。《金匮要略》把这一点说得很清楚 —— 它靠列「什么没有出问题」来说：小便自利、饮食如故、反不渴。这三条阴性发现就是它的论证。肾病水肿的人不会被这样描述，血糖失控那种口渴多尿的人也不会。古典原文正在把这个主诉从它借用的那个脏器名字上摘开。看到「肾」字就以为自己得了肾病，做的恰好是原文没有做的事。
剩下这幅图景值得细读：身体重；腰中冷、如坐水中；以及那句人人都记得的「腹重如带五千钱」。腰痛伴沉重感，今天是一张鉴别表而不是一个诊断。其中包含机械性与退行性原因 —— 最常见，也最良性；也包含椎体压缩骨折、脊柱感染（椎间盘炎、硬膜外脓肿）、转移性恶性肿瘤、骨髓瘤、腹主动脉瘤与夹层（后者古典式地表现为撕裂样痛，以小时计）、肾绞痛、肾盂肾炎、向背部放射的胰腺炎，以及马尾综合征。
红旗症状是这张表存在的理由，值得直说：新出现的小便或大便失禁或潴留、鞍区麻木、进行性下肢无力、发热、夜间痛醒、不明原因体重下降、癌症史、长期用皮质类固醇、静脉吸毒、明显外伤，以及五十岁以上新发的腰痛。马尾综合征是外科急症，它靠大小便功能改变来宣告自己，而不是靠疼痛程度。
古典的病因观值得留下：身劳汗出，衣里冷湿，久久得之 —— 劳作出汗后，冷湿的衣服贴在身上，久而久之。这是职业与环境的观察，比多数古典病因具体得多。
药物本身：甘草带甘草酸问题 —— 假性醛固酮增多症式的钠水潴留伴失钾，与排钾利尿剂、地高辛或蒽醌类泻药同用时风险最大。茯苓是真菌的菌核，**不是土茯苓**（Smilax glabra）—— 名字极像而实为两物。干姜是浓缩的辛温之品。白术是菊科根茎，菊科接触性皮炎常见。肾着汤之名在后世文献中对应的组成不止一种；本库记《金匮要略》四味这一版，不裁决各版本异同。孕期与哺乳期没有充分的人体安全性数据。中文文献里这方用于腰痛的临床观察规模小、多为非对照；本库如实记「研究存在」，不记「疗效已被确立」。