Source 出处 · Jingyue Quanshu · Doses are not given here: they are set by a licensed practitioner for the individual.
Safety. Zuo Gui Wan comes from Jingyue Quanshu, the collected work of Zhang Jiebin (Zhang Jingyue), a Ming-dynasty physician who rebuilt kidney theory around the idea of the gate of life. The name is a paired one: Zuo Gui Wan, the left-restoring pill, and You Gui Wan, the right-restoring pill. The left and right here are not anatomy. In the classical framing the left kidney governs water and stores essence, the right governs fire and the gate of life; the two pills are the two halves of one argument. Zhang stated it in a line that is still quoted: to supplement yang well one must seek yang within yin, and to supplement yin well one must seek yin within yang, because yin that is lifted by yang does not run dry.
Read against Liu Wei Di Huang Wan, the composition is instructive. Zuo Gui Wan keeps the three supplementing herbs of that formula - prepared rehmannia, Chinese yam, cornelian cherry - and drops the three draining ones (alisma, poria, moutan). In their place it adds goji berry, dodder seed, cyathula, and the two animal glues. Zhang called this supplementing without draining, and it is the reason this formula is described as heavier and more cloying than the six-ingredient pill.
Three things are worth saying plainly. First, the kidney in this tradition is a functional system, not the anatomical organ and not the nephrology clinic. Fatigue, sore lower back, dizziness, tinnitus and failing memory are the picture the formula is aimed at, and every one of them is also produced by anaemia, thyroid disease, depression, diabetes, chronic kidney disease, obstructive sleep apnoea, low testosterone and deficiency of vitamin B12 or D. Several of those are separated from the classical picture by a single blood test. Second, the two glues are animal products. Deer antler glue comes from a farmed cervid and tortoise shell glue from a chelonian; most turtle species are listed in the CITES appendices, and both materials are subject to wildlife and customs control. That is a practical matter when carrying or shipping them across borders, and it is a reason for vegetarian readers to look elsewhere. Third, goji berry has published case reports of interaction with warfarin. Cyathula is one of two herbs traded as niu xi and it is contraindicated in pregnancy. Prepared rehmannia is not the same material as raw rehmannia, and cornelian cherry (shan zhu yu) is unrelated to evodia (wu zhu yu) despite the similar name. Honey pills carry sugar. A thick, cloying formula of this kind is traditionally avoided where the digestion is weak, the appetite poor or the stool loose, and it is not used during an acute illness.
左归丸出自《景岳全书》，作者张介宾（张景岳）是明代把肾与命门学说重新整理过一遍的医家。方名是成对的：「左归」与「右归」。这里的左右不是解剖：古典框架里左肾属水主藏精，右肾属火属命门，两首方是同一个论证的两半。张氏有一句常被引用的话 —— 善补阳者必于阴中求阳，善补阴者必于阳中求阴，阴得阳升而泉源不竭。
拿它与六味地黄丸对读最能看出意图。左归丸保留了六味里「三补」的熟地、山药、山茱萸，去掉「三泻」的泽泻、茯苓、丹皮，改配枸杞、菟丝、牛膝与龟鹿二胶。张氏称此为「补而无泻」，这也是它被认为比六味更滋腻厚重的原因。
三件事必须说清。第一，这里的「肾」是藏象功能系统，不是解剖器官，也不是肾内科。腰膝酸软、头晕耳鸣、疲乏健忘是它所对的画面，而这些表现同样由贫血、甲状腺疾病、抑郁、糖尿病、慢性肾病、睡眠呼吸暂停、低睾酮、维生素 B12 或 D 缺乏引起，其中若干项与古典画面之间只隔着一次血液检查。第二，两味胶是动物制品：鹿角胶取自养殖鹿类，龟板胶取自龟类；多数龟种列入 CITES 附录，两种材料都受野生动物与海关监管，跨境携带或邮寄是实际会遇到的问题，也是素食者应当考虑的一点。第三，枸杞子与华法林相互作用的病例报告有文献记载；牛膝一名两物（牛膝与川牛膝）且孕期禁用；熟地黄与生地黄不是同一物；山茱萸与吴茱萸只是名字相近，来源无关。蜜丸含糖。脾胃虚弱、纳差便溏者传统上忌用此类滋腻方，外感与急性病期也不适用。