主治小便不利冒眩也。旁治渴。
考 证
泽泻汤证曰∶心下有支饮、其人苦冒眩。
五苓散证曰∶小便不利、微热消渴。
以上二方，以泽泻为君药。泽泻汤，泽泻五两，五苓散一两六铢半。
茯苓泽泻汤证曰∶吐而渴欲饮水。
以上一方，泽泻四两。
八味丸证曰∶小便不利。又曰∶消渴、小便反多。
以上一方，泽泻三两。
猪苓汤证曰∶渴欲饮水、小便不利。
以上一方，泽泻一两。
牡蛎泽泻散证曰∶从腰以下有水气。
以上一方，用泽泻与余药等分。茯苓泽泻汤以下四方，以泽泻为佐药也。
上历观此诸方，泽泻所主治也，不辨而明矣。
互 考
泽泻、五味子，同治冒而有其别也。说见于五味子部中。
辨 误
陶弘景曰∶泽泻久服则无子。陈日华曰∶泽泻催生，令人有子。李时珍辨之，其论详于
《本草纲目》。夫怀孕，妇人之常也，而有病不孕，故其无病而孕者，岂其药之所能得失乎？
三子不知此义，可谓谬矣。余尝治一妇人，年三十有余，病而无子，有年于兹。诸医无如之
何，余为诊之。胸膈烦躁、上逆而渴，甚则如狂，乃与石膏黄连甘草汤，并以滚痰丸服之。
周岁，诸证尽愈。其父大喜，以语前医。前医曰∶治病则可，而不仁也。曰∶何谓也？曰多
服石膏，无子也，是绝妇道也。非不仁而何？其父愕然，招余诘之。余答曰∶医者掌疾病者
也。而孕也者，人为而天赋，医焉知其有无哉？且彼人之言，子何不察焉？彼人疗之十有三
年，而不能治之，彼岂豫知其来者乎？其父曰∶然。居顷之，其妇人始孕也。弥月而娩，毋
子无
品 考
泽泻 本邦仙台所出者，是为良也。锉用。
主治小便不通畅、头晕目眩。兼治口渴。
考证
泽泻汤证表现为：心下有支饮，患者深受头晕目眩之苦。
五苓散证表现为：小便不通畅，微热且消渴（极度口渴）。
以上两个方剂，以泽泻为君药（主药）。泽泻汤中，泽泻用量为五两；五苓散中，泽泻用量为一两六铢半。
茯苓泽泻汤证表现为：呕吐且想喝水。
以上一个方剂，泽泻用量为四两。
八味丸（即金匮肾气丸）证表现为：小便不通畅。又说：消渴，小便反而增多。
以上一个方剂，泽泻用量为三两。
猪苓汤证表现为：想喝水，小便不通畅。
以上一个方剂，泽泻用量为一两。
牡蛎泽泻散证表现为：腰部以下有水气停留。
以上一个方剂，泽泻与其余药物等量配伍。从茯苓泽泻汤以下的四个方剂来看，泽泻是作为佐药使用的。
综上所述，纵观这些方剂，泽泻所主治的功效，是不言自明的。
互考
泽泻与五味子都能治疗头晕目眩，但二者有区别。详细论述见五味子条目中。
辨误
陶弘景说：长期服用泽泻会导致没有种子（指植物不结籽或引申为无子嗣）。陈日华说：泽泻能催生，让人有子嗣。李时珍对此进行了辨析，其论述详见《本草纲目》。怀孕，是妇女的常态，但有病导致不孕，所以那些没病而怀孕的人，难道是靠药物来决定是否有子嗣的吗？这三位医家不懂这个道理，可以说是谬误了。我曾经治疗一位三十多岁的妇人，患病多年而无子嗣。各位医生都束手无策，我为她诊脉。她胸膈烦闷躁扰，气机上逆且口渴，严重时神志狂乱，于是给予石膏黄连甘草汤，并配合滚痰丸服用。一年后，所有症状全部痊愈。她的父亲非常高兴，将此事告诉了之前的医生。之前的医生说：治病是可以的，但这太不仁义了。问：什么意思？答：长期服用石膏，会导致没有子嗣，这是断绝妇人的生育之道。这不是不仁义是什么？她的父亲感到愕然，招我前来质问。我回答说：医生的职责是掌管疾病的治疗。而怀孕这件事，既有后天人为的因素，也有天赋自然的成分，医生怎么知道她是否有生育能力呢？况且，你为什么不考察一下那位医生的言论呢？他治疗了十三年，都没能治好她，他难道预先知道她能怀孕吗？她的父亲说：确实如此。过了不久，这位妇人开始怀孕。满十月后分娩，母子平安。
Translation:
It primarily treats difficulty in urination accompanied by dizziness and vertigo. It secondarily treats thirst.
Evidence
The syndrome of Zexie Tang (Alisma Decoction) is described as: "Fluid retention under the heart, causing severe dizziness and vertigo."
The syndrome of Wuling San (Five-Ingredient Powder with Poria) is described as: "Difficulty in urination, slight fever, and excessive thirst."
In the above two formulas, Alisma Rhizome (Zexie) serves as the Jun herb (chief ingredient). In Zexie Tang, the dosage of Alisma Rhizome is five liang; in Wuling San, the dosage is one liang and six zhu half.
The syndrome of Fuling Zexie Tang (Poria and Alisma Decoction) is described as: "Vomiting accompanied by a desire to drink water."
In the above formula, the dosage of Alisma Rhizome is four liang.
The syndrome of Bawei Wan (Eight-Ingredient Pill, i.e., Jin Gui Shen Qi Wan) is described as: "Difficulty in urination." It also states: "Excessive thirst, yet urination is frequent."
In the above formula, the dosage of Alisma Rhizome is three liang.
The syndrome of Zhuling Tang (Polyporus Decoction) is described as: "Desire to drink water, accompanied by difficulty in urination."
In the above formula, the dosage of Alisma Rhizome is one liang.
The syndrome of Muli Zexie San (Oyster and Alisma Powder) is described as: "Water qi accumulation below the waist."
In the above formula, Alisma Rhizome is used in equal proportion to the other herbs. From Fuling Zexie Tang onwards, in these four formulas, Alisma Rhizome serves as the Zuo herb (assistant ingredient).
Having reviewed all these formulas, the therapeutic indications of Alisma Rhizome are self-evident.
Cross-Reference
Alisma Rhizome (Zexie) and Schisandra Fruit (Wuweizi) both treat dizziness and vertigo, but they differ in their actions. Detailed explanations can be found in the entry for Wuweizi.
Correction of Errors
Tao Hongjing stated: "Long-term consumption of Alisma Rhizome results in no seeds." Chen Rihua stated: "Alisma Rhizome induces labor and enables conception." Li Shizhen refuted these claims, with detailed arguments presented in *Bencao Gangmu* (Compendium of Materia Medica). Pregnancy is a normal physiological state for women. Those who suffer from infertility due to illness cannot conceive simply because they take herbs. Therefore, those who conceive without illness are not necessarily influenced by drugs. The ignorance of these three physicians regarding this principle constitutes a fallacy.
I once treated a woman over thirty years old who had been infertile due to illness for many years. Previous physicians were unable to help her. Upon diagnosis, I found her suffering from chest and diaphragm irritability, rebellious qi causing thirst, and in severe cases, delirium. I prescribed Shigao Huanglian Gancao Tang (Gypsum, Coptis, and Licorice Decoction) along with Guntan Wan (Rolling Phlegm Pill). After one year, all symptoms resolved completely. Her father was delighted and informed the previous physician. The previous physician remarked, "Treating the disease is acceptable, but it is unkind." When asked why, he replied, "Long-term use of Gypsum leads to infertility, cutting off the woman's reproductive capacity. Is this not unkind?" The father was astonished and summoned me to question my methods. I replied, "A physician's duty is to treat diseases. Conception involves both human effort and natural endowment; how can a physician predict fertility? Moreover, why did you not examine that physician's track record? He treated her for thirteen years without success; did he foresee her future pregnancy?" The father agreed. Shortly thereafter, the woman became pregnant. She delivered a healthy baby after full term.
Quality Assessment
Alisma Rhizome (Zexie): That produced in Sendai, our country, is of superior quality. It should be sliced before use.