Source 出处 · Jingui Yaolüe · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Huangqi Jianzhong Tang is what happens when one ingredient is added to a formula that already exists: it is Xiao Jianzhong Tang plus huang qi, milkvetch root. The base formula is itself a modification — cinnamon twig decoction with the peony doubled and maltose added — so this is a third-generation composition, and the lineage is worth stating plainly because the names in this family are easy to confuse. The line it is recorded for in the Jingui Yaolüe is short: 虚劳里急，诸不足 — a state of depletion, a sensation of internal cramping or urgency, and "various insufficiencies."
The honest modern observation is that 虚劳 is not a diagnosis. It is a description of a person who is tired, thin, and not thriving. Today that description maps onto a differential that has to be worked through rather than tonified: unintentional weight loss, iron-deficiency anaemia, coeliac disease, thyroid disease and diabetes, inflammatory bowel disease, chronic infection including tuberculosis, obstructive sleep apnoea, depression, and malignancy. Guidance in most countries treats unexplained weight loss as an indication for investigation, not for a tonic. A second and more specific point: 里急 — cramping abdominal discomfort with a sense of urgency — is also how irritable bowel syndrome, bile acid diarrhoea, microscopic colitis and colorectal cancer can each begin, and the features that move someone from reassurance to endoscopy (blood in the stool, new onset after the screening age, symptoms that wake a person from sleep, anaemia) are the same ones that make depletion a poor explanation.
Two composition facts deserve to sit next to that. First, 饴糖 is maltose, and this decoction therefore carries a substantial sugar load. That is not a neutral matter for a person with diabetes or impaired glucose tolerance — and the people described as 虚 are often exactly the people who have lost weight and are being investigated for diabetes. Second, 甘草 (liquorice) contains glycyrrhizin, and sustained intake of glycyrrhizin can produce a mineralocorticoid-like picture: sodium and water retention, potassium loss, and raised blood pressure. Potassium loss is the mechanism by which it becomes dangerous alongside digoxin or a thiazide or loop diuretic, and cases of hypokalaemic weakness and arrhythmia from liquorice are reported in the clinical literature.
Identity matters as much as mechanism. 黄芪 is the root of Astragalus membranaceus or A. mongholicus; it is not 红芪, which is a Hedysarum root, and the genus contains species that accumulate swainsonine, the alkaloid behind locoweed poisoning, which is why substitution inside this genus is not a trivial matter. 芍药 here means 白芍, not 赤芍, and peony is named in the classical 十八反 incompatibility with 藜芦 (Veratrum). 黄芪 shows immunomodulatory activity in preclinical work; what that means for someone taking immunosuppressive medicine after a transplant, or living with autoimmune disease, is not settled, and this entry does not settle it.
The formula is recorded here as a document of how a classical text handled depletion. It is not a substitute for finding out why a person is losing weight.
黄芪建中汤著录于《金匮要略》，本方是在一张已有方子上加一味的结果：小建中汤再加黄芪。而小建中汤本身又是一张改方（桂枝汤倍芍药加饴糖），所以这是第三代组成；这个脉络值得写清楚，因为这一家子的方名极易混淆。条文极短：**虚劳里急，诸不足**。
老实说，「虚劳」不是一个诊断，它是对一个疲乏、消瘦、状态不旺的人的描述。今天这个描述对应的是一串要排查的名单，而不是要补的对象：不明原因体重下降、缺铁性贫血、乳糜泻、甲状腺疾病与糖尿病、炎症性肠病、含结核在内的慢性感染、睡眠呼吸暂停、抑郁，以及肿瘤。各国指南都把不明原因体重下降当作**检查指征**，而不是进补指征。更进一步说：「里急」这种腹中拘急窘迫的感觉，也是肠易激、胆汁酸性腹泻、显微镜下结肠炎乃至结直肠癌各自的起病方式；而把一个人从「宽慰」推向「内镜」的那些特征（便血、筛查年龄后新发、夜间症状、贫血），恰恰就是让「虚劳」成为一个坏解释的那几条。
组成里有两件事必须放在一起讲。其一，**饴糖是麦芽糖** —— 这碗汤带着一次真实的糖负荷。对糖尿病或糖耐量受损的人这不是中性事件，而被描述为「虚」的人往往正是已经消瘦、正在查糖尿病的那批人。其二，**甘草含甘草酸**，持续摄入可产生盐皮质激素样表现：钠水潴留、失钾、血压升高；而失钾正是它与地高辛或噻嗪类/袢利尿剂同用时变危险的机制，临床上由甘草引起低钾性肌无力与心律失常的报道是实在的。
辨物与讲机制同样重要：**黄芪**是膜荚黄芪或蒙古黄芪的根，不是**红芪**（岩黄芪属），而黄芪属内有含**苦马豆素**（疯草中毒的那个生物碱）的种类，所以这个属内的替代不是小事。方中的**芍药是白芍不是赤芍**，且芍药在十八反中与藜芦相对。黄芪在临床前研究中显示免疫调节活性；这对移植后服用免疫抑制剂的人、或对自身免疫病的人意味着什么，目前没有定论，本条也不裁决。
本方在这里是作为「古典文献如何处理虚损」的一份记录被收录。它不能替代去查明一个人为什么在消瘦。