《金匮要略》曰∶问病有血分水分，何也？师曰∶经水前断，后病水，名曰血分，此病为难治。先病水，后
断经水，名曰水分，此病易治。何以故？去水其经自下也。
《圣济总录》曰∶血分者，经水通之际，因寒湿伤其冲任，气壅不行，播在皮肤，邪气相搏，经血分而为
水，发为 肿，故曰血分。《脉经》曰∶经水前断，后病水者，名曰血分，久不治，积成水肿，即难治。
《圣济总录》曰∶水分者，以水气上溢皮肤，散于四肢，发为 肿。盖肾者，胃之关，关门不利，故聚水
而从其类也。此病与血分相似，治药有先后耳。
汪石山曰∶凡经先断，而后病水，少阴脉沉而滑，沉则在里，滑则为实，沉滑相搏，血结胞门，为血分，难
治。若先病水，而后病经断，少阳脉牢，少阴脉细，男子小便不利，妇人经水不通，经通则为血，不利则为
水，名水分，易治。此因脾肺虚冷，不能通调水道，下输膀胱，渗泄之令不行，生化之气不运。东垣云，水饮留
积，若土在雨中则为泥，得和气暖日，水湿去而万物自生长，用加减肾气丸、归脾汤、六君子加木香、炮姜、肉桂。
陈良甫曰∶妇人经水不通，则水化为血，血不通则复化为水。故先因经水断绝，后四肢浮肿，小便不通，名
曰血分，是血化为水也，宜椒仁丸。若先因小便不通，后身面浮肿，致经水不通，名曰水分，是水化为血也，
宜葶苈丸。经脉不通而化为水，流走四肢悉肿满，亦名血分，其证与水证相类，实非水也，用人参丸。
张 璜按∶先浮肿而后经水不通，明系吐虚不能制水，经虚则血不能生，故经止。若水化为血等语，真堪捧腹。
《金匮要略》说：问疾病有血分和水分，是什么道理呢？老师说：月经先停止，后来发生水肿病的，名叫血分，这种病难以治疗。先发生水肿病，后来月经停止的，名叫水分，这种病容易治疗。为什么这样呢？因为去除了水邪，月经自然就会通畅下行。
《圣济总录》说：所谓血分，是在月经来潮之际，因寒湿损伤了冲脉和任脉，气机壅滞不通，水湿散布在皮肤之间，邪气相互搏结，经血分离而化为水，发为浮肿，所以叫作血分。《脉经》说：月经先停止，后来发生水肿病的，名叫血分，如果长期不治疗，积聚而成水肿，就难以治愈。
《圣济总录》又说：所谓水分，是因为水气上溢至皮肤，散播于四肢，发为浮肿。肾是胃的关口，如果这个关口功能不利，就会导致水液聚集并同类相从。这种病与血分相似，只是治疗的用药先后顺序不同罢了。
汪石山说：凡是月经先停止，后来才发生水肿病的，少阴脉象沉而滑，沉脉主里证，滑脉主实证，沉脉与滑脉相搏结，说明血液结聚在胞宫之门，属于血分，难以治疗。如果是先发生水肿病，后来才导致月经停止，少阳脉象牢，少阴脉象细，男子小便不利，妇人月经不通，月经通畅则化为血，小便不利则化为水，这叫水分，容易治疗。这是因为脾肺虚冷，不能通调水道，向下输送到膀胱，渗泄的功能不行，生化之气不运行。李东垣说过，水饮留积，就像土在雨中变成泥一样，得到和气暖日的照耀，水湿去除后万物自然生长，可用加减肾气丸、归脾汤、六君子汤加木香、炮姜、肉桂。
陈良甫说：妇人月经不通，水就会化为血；血不通畅，又会重新化为水。所以如果先因月经断绝，后来出现四肢浮肿、小便不通，名叫血分，这是血化为水的表现，适宜用椒仁丸。如果先因小便不通，后来导致身面浮肿，进而引起月经不通，名叫水分，这是水化为血的表现，适宜用葶苈丸。经脉不通畅而化为水，流注走窜于四肢，全身都肿胀满闷，也名叫血分，其症状与水证相似，但实际上并非水邪所致，用人参丸。
张璜按语：先出现浮肿而后月经不通，明显是脾气虚弱不能制约水湿，经血亏虚则血不能化生，所以月经停止。至于像“水化为血”之类的说法，实在令人捧腹大笑。
The *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet) states: One asks, what are blood differentiation and water differentiation in diseases? The Master replies: If menstruation ceases first, followed by the onset of edema, it is named blood differentiation; this condition is difficult to treat. If edema occurs first, followed by the cessation of menstruation, it is named water differentiation; this condition is easy to treat. Why is this? Because once the pathogenic water is eliminated, menstruation will naturally flow downward.
The *Shengji Zonglu* (Compendium of Holy Relief) states: Blood differentiation refers to a situation where, at the time of menstruation, cold-dampness injures the Chong and Ren vessels. Qi becomes stagnant and fails to circulate, causing fluid retention to spread across the skin. Pathogenic factors contend with each other, separating menstrual blood into water, resulting in edema; hence it is called blood differentiation. The *Maijing* (Pulse Classic) states: When menstruation stops first and edema follows, it is named blood differentiation. If left untreated for a long time, it accumulates into severe edema, becoming difficult to treat.
The *Shengji Zonglu* further states: Water differentiation occurs when water qi overflows onto the skin and disperses into the four limbs, causing edema. The Kidney serves as the gatekeeper of the Stomach; if this gate functions improperly, water accumulates and gathers according to its kind. This condition resembles blood differentiation, differing only in the sequence of treatment and medication.
Wang Shishan states: Whenever menstruation ceases first, followed later by edema, the Shaoyin pulse is deep and slippery. A deep pulse indicates interior syndrome, while a slippery pulse indicates excess syndrome. The combination of deep and slippery pulses signifies blood stasis obstructing the uterine gate, constituting blood differentiation, which is difficult to treat. Conversely, if edema occurs first, followed by the cessation of menstruation, the Shaoyang pulse is firm, and the Shaoyin pulse is thin. In men, there is difficulty urinating; in women, menstruation is blocked. When menstruation flows freely, it transforms into blood; when urination is obstructed, it transforms into water. This is named water differentiation and is easy to treat. This arises from deficiency-cold of the Spleen and Lung, which fail to regulate water passages and transport fluids downward to the Bladder. The mechanism of seepage and excretion fails, and the vitalizing energy does not circulate. Li Dongyuan stated that retained water-drink accumulation is like soil turning to mud in the rain; exposed to harmonious air and warm sunlight, the water and dampness dissipate, allowing all things to grow naturally. Treatments include Jiajian Shenqi Wan (Modified Kidney Qi Pill), Guipi Tang (Restore the Spleen Decoction), or Liu Junzi Tang (Six Gentlemen Decoction) augmented with Muxiang (Aucklandiae Radix), Paojiang (Prepared Ginger), and Rougui (Cinnamon Bark).
Chen Liangfu states: In women, if menstruation is blocked, water transforms into blood; if blood circulation is obstructed, it reverts to transforming into water. Therefore, if menstruation ceases first, followed by edema of the four limbs and urinary obstruction, it is named blood differentiation, representing blood transforming into water; Jiaoren Wan (Pepper Seed Pill) is appropriate. If urinary obstruction occurs first, leading to facial and bodily edema, which subsequently causes menstrual blockage, it is named water differentiation, representing water transforming into blood; Tingli Wan (Descurainia Seed Pill) is appropriate. If meridian blockage leads to transformation into water, which flows through the four limbs causing generalized swelling and fullness, it is also named blood differentiation. Although its symptoms resemble water syndromes, it is essentially not caused by water pathogens; Ren Shen Wan (Ginseng Pill) should be used.
Zhang Huang's commentary: Edema appearing first, followed by menstrual blockage, clearly indicates Spleen Qi deficiency failing to control water, and Meridian blood deficiency failing to generate blood, thus stopping menstruation. Statements such as "water transforming into blood" are truly laughable.