(此篇熟究，调经之事至矣尽矣，幸毋忽之)
丹溪云∶经水者，阴血也。阴必从阳，故其色红，禀火色也。随气流行于上下三焦之间
，气
清血亦清，气浊血亦浊。往往有成块者，气之凝也。将行而痛者，气之滞也。来后而痛者，
气血俱虚也。色淡者，气虚而有水混之也。错经妄行者，气之乱也。紫者，气之热也。黑者
，热之甚也。今人但见其紫者、黑者、作痛者、成块者，率指为冷风而行温热之剂，则祸不
旋踵矣。良由《病源论》月水诸病，皆由风冷乘之，宜其相习而成俗也。或曰黑者，北方水
色也。紫淡于黑，非冷而何?予曰∶亢则害，承乃制。热甚者必兼水化，所以热则紫，甚则
黑也。殊不知妇人性执见偏，嗜欲倍加，脏腑阴阳之火无日不起，非热而何?若夫风冷，必
须外得，间或有之。至于风冷为病，外邪初感，入经必痛，紫黑成块，暂用温散，但寒性稍
久便郁成热，岂可专泥为寒耶?且寒则凝泣，热则流通，暴下紫黑，尤非寒症明矣。然脐腹
内痛不特风冷，亦有属气滞者，为气有余便是火也。有属血虚者，为血不足便生热也，又安
可用温热乎?大抵紫黑者，四物汤加芩、连、阿胶。淡白者，芎归汤加参、术、白芍。淡黄
，二陈汤加芎、归。色如烟尘者，二陈汤加秦艽、防风、苍术。
(If this chapter is thoroughly studied, the principles of regulating menstruation will be fully understood; do not neglect it.)
Zhu Danxi said: Menstrual blood is Yin blood. Yin necessarily follows Yang, therefore its color is red, inheriting the hue of Fire. It circulates up and down within the San Jiao (Triple Burner) along with Qi. When Qi is clear, Blood is also clear; when Qi is turbid, Blood is also turbid. Often, clots form due to the stagnation of Qi. Pain before the onset of menstruation is caused by Qi stagnation. Pain after the onset of menstruation indicates deficiency of both Qi and Blood. A pale color suggests Qi deficiency mixed with Dampness. Irregular or profuse bleeding results from the disorder of Qi. A purple color indicates Heat in the Qi level. A black color signifies extreme Heat. Nowadays, people merely observe purple or black colors, pain, and clots, and generally attribute them to Cold Wind (Cold pathogen), prescribing warm and hot agents. Consequently, disaster ensues immediately. This is largely because *The Source of Diseases* (*Bing Yuan Lun*) stated that various menstrual disorders are caused by Cold Wind invading the body, leading to a habitual acceptance of this view. One might ask: Black is the color of Water in the North. Purple is lighter than black; is it not Cold? I reply: When conditions reach an extreme, they cause harm; only through control can balance be maintained. Extreme Heat must manifest with characteristics of Water transformation; thus, Heat presents as purple, and extreme Heat as black. They fail to realize that women often have stubborn dispositions and biased views, with excessive desires, causing the Fire of Yin and Yang in the Zang-Fu organs to rise daily. Is this not Heat? As for Cold Wind, it must originate externally and occurs only occasionally. Regarding diseases caused by Cold Wind, when external pathogens first invade, entering the meridians causes pain, resulting in purple-black color and clots. Temporarily using warm dispersal methods may help, but Cold nature tends to stagnate and transform into Heat over time. How can one rigidly adhere to the diagnosis of Cold? Moreover, Cold causes coagulation and stagnation, while Heat promotes flow. Sudden profuse discharge of purple-black blood clearly indicates it is not a Cold syndrome. However, pain inside the umbilical and abdominal regions is not solely due to Cold Wind; it may also belong to Qi stagnation, as "excess Qi becomes Fire." It may also belong to Blood deficiency, as "insufficient Blood generates Heat." How then can warm and hot agents be used? Generally, for purple-black color, use Si Wu Tang (Four Substances Decoction) added with Huang Qin (Scutellaria Root), Lian Zi (Lotus Plumule), and E Jiao (Donkey-hide Gelatin). For pale-white color, use Xiong Gui Tang (Ligusticum and Angelica Decoction) added with Ren Shen (Ginseng Root), Bai Zhu (Atractylodes Rhizome), and Bai Shao (White Peony Root). For pale-yellow color, use Er Chen Tang (Two-Aged Decoction) added with Chuan Xiong (Sichuan Lovage Rhizome) and Dang Gui (Angelica Sinensis). For a color resembling smoke and dust, use Er Chen Tang (Two-Aged Decoction) added with Qin Jiao (Gentiana Macrophylla Root), Fang Feng (Saposhnikovia Root), and Cang Zhu (Atractylodes Lancea Rhizome).