血者水谷之精气，若伤脾胃何以生，不调液竭血枯病，合之非道损伤成。
【注】血者，水谷之精气也。在男子则化为精；在妇人则化为血，上为乳汁，下为月
水。若内伤脾胃，健运失职，饮食减少，血无以生，则经必不调。亦有女子天癸既至、逾
期不得与男子合，未期思与男子合，与夫经正行时而合，此皆合之非道，亦致不调。或
过淫、合多则液竭，产多、乳众则血枯，亦皆能损伤阴血致成经病也。
血从阳化色正红，色变紫黑热之征，黄泔淡红湿虚化，更审瘀块黯与明。
【注】血属阴，从阳化，故其色以正红为正，虽有经病，亦易为治也。若色变深红、紫
黑，乃热之征也。或黄如米泔，乃湿化也。浅淡红白，乃虚象也。更当审其有瘀、有块、色
黯、色明以治之。若黯而紫黑，兼见冷证，多属寒凝；若明而紫黑，见热证，多属热结也。
热化稠粘臭必秽，寒化清彻臭则腥，内溃五色有脏气，时下而多命必倾。
【注】凡血为热所化，则必稠粘臭秽；为寒所化，则必清彻臭腥。若是内溃，则所下
之物杂见五色，似乎脓血。若更有脏腐败气，且时下不止而多者，是危证也，其命必倾矣！
经来前后为愆期，前热后滞有虚实，淡少为虚不胀痛，紫多胀痛属有余。
【注】经来或前或后，谓之愆期，皆属经病。经来往前赶，日不足三旬者，属血热。若
下血多，色深红而浊，则为有余之热；若下血少，色浅淡而清，则为不足之热也。经来
往后退，日过三旬后者，属血滞。若色浅淡、血少，不胀痛者，则属气虚，血少涩滞，不
足之病；若色紫、血多，腹胀痛者，则属气实，血多瘀滞，有余之病也。
血液，是饮食水谷所化生的精微物质。如果脾胃受损，如何能生成血液？导致月经不调、津液枯竭、血液枯槁的病症，往往是由不正常的性行为损伤而形成的。
【注】血液，是水谷精微转化而成的。在男性则转化为精；在女性则转化为血，上行成为乳汁，下行成为月经。如果内伤脾胃，运化功能失职，饮食减少，血液无法生成，那么月经必定不调。也有女子天癸（促进生殖机能成熟的物质）已经到来，超过婚期却未能与男子交合，未到婚期却思念与男子交合，或者在月经正常行经期间进行房事，这些都属于不合常理的性行为，也会导致月经不调。或者纵欲过度、房事频繁则耗竭阴液，生产过多、哺乳过久则血液枯槁，这些都足以损伤阴血从而形成月经病。
经血由阳气化生，颜色正红为正常；颜色变为紫黑色，是热象的表现；颜色如米泔水或淡红色，是湿邪或虚损化生的表现，还需进一步审查是否有瘀血、血块，以及颜色的晦暗或鲜明。
【注】血属于阴，但需依赖阳气才能化生，所以其颜色以正红为正常，即使有月经病，也易于治疗。如果颜色变为深红、紫黑，这是热象的表现。或者颜色黄如米泔水，这是湿邪化生的表现。颜色浅淡红白，这是虚损的表现。更应当审查是否有瘀血、血块，颜色晦暗或鲜明来进行治疗。如果颜色晦暗且紫黑，兼见寒证，多属于寒凝；如果颜色鲜明且紫黑，见热证，多属于热结。
热邪化生的经血稠粘且有秽臭味；寒邪化生的经血清澈且有腥臭味；体内脏器溃烂下出的五色分泌物带有脏腑腐败气味，如果时下量多不止，生命必然危险。
【注】凡是血液被热邪所化，就一定稠粘且有秽臭味；被寒邪所化，就一定清澈且有腥臭味。如果是内脏溃烂，那么所排出的物体混杂呈现五色，似乎像脓血。如果更有脏腑腐败的气味，并且时下量多不止，这是危重证候，生命必然倾覆！
月经提前或推后称为经期不准（愆期），提前的多为热证，推后的多为滞证，均有虚实之分。颜色淡、量少为虚证，不胀痛；颜色紫、量多且胀痛属实证（有余）。
【注】月经来潮或提前或推后，称为经期不准，都属于月经病。月经来潮提前，不足三十天的，属于血热。如果出血多，颜色深红浑浊，则为实热；如果出血少，颜色浅淡清稀，则为虚热。月经来潮推后，超过三十天的，属于血滞。如果颜色浅淡、血量少，不胀痛，则属于气虚，血少涩滞，属于虚损之病；如果颜色紫、血量多，腹胀痛，则属于气实，血多瘀滞，属于实证（有余）。
Blood is the essence derived from food and fluids. If the Spleen and Stomach are damaged, how can blood be generated? Disorders of menstruation, exhaustion of body fluids, and depletion of blood often result from improper sexual conduct causing injury.
[Note] Blood is transformed from the essence of food and fluids. In men, it transforms into Essence (Jing); in women, it transforms into Blood, ascending to become milk and descending to become menstrual water. If internal damage occurs to the Spleen and Stomach, impairing their transportation and transformation functions, leading to reduced dietary intake, blood cannot be generated, resulting inevitably in irregular menstruation. There are also cases where a woman has reached menarche (Tian Gui) but has not cohabited with a man past her marriageable age, or desires cohabitation before the appropriate time, or engages in intercourse during normal menstruation. These constitute improper sexual conduct, which also leads to menstrual irregularities. Excessive lust or frequent intercourse depletes Yin fluids; excessive childbirth or prolonged lactation depletes Blood. All these can damage Yin and Blood, thereby forming menstrual diseases.
Menstrual blood is transformed by Yang Qi; a bright red color is normal. A change to purple-black indicates Heat. A color resembling rice washings or pale red indicates Dampness or deficiency transformation. One must further examine for the presence of stasis, clots, and whether the color is dull or bright.
[Note] Blood belongs to Yin but requires Yang Qi for transformation; thus, a bright red color is considered normal. Even if menstrual disorders exist, they are easy to treat. If the color becomes deep red or purple-black, this is a sign of Heat. If yellow like rice washing water, it indicates transformation due to Dampness. If pale red or white, it indicates a Deficiency pattern. One must further examine for the presence of stasis, clots, and whether the color is dull or bright to guide treatment. If the color is dull and purple-black, accompanied by Cold signs, it mostly belongs to Cold Coagulation; if the color is bright and purple-black, accompanied by Heat signs, it mostly belongs to Heat Binding.
Heat-transformed blood is thick, sticky, and foul-smelling; Cold-transformed blood is clear and thin with a fishy odor. Internal organ ulceration discharges substances mixed with five colors, resembling pus and blood. If there is a rotten organ odor and profuse, continuous discharge, it is a critical condition, and life will surely be endangered.
[Note] When blood is transformed by Heat, it is necessarily thick, sticky, and foul-smelling; when transformed by Cold, it is necessarily clear, thin, and fishy-smelling. If it is due to internal organ ulceration, the discharged material appears mixed with five colors, resembling pus and blood. If accompanied by a rotten organ odor and profuse, continuous discharge, this is a critical syndrome, and life is at risk.
Menstruation occurring early or late is termed "Irregular Period" (Qian Qi). Early onset is associated with Heat; late onset is associated with Stagnation. Both have Deficiency and Excess patterns. Pale color and scant flow indicate Deficiency without distending pain; purple color and abundant flow with distending pain indicate Excess.
[Note] Menstruation arriving either early or late is called Irregular Period, belonging to menstrual disorders. Menstruation arriving early, less than thirty days apart, belongs to Blood Heat. If bleeding is heavy with deep red, turbid blood, it is Excess Heat; if bleeding is light with pale, clear blood, it is Deficient Heat. Menstruation arriving late, more than thirty days apart, belongs to Blood Stagnation. If the color is pale, blood volume is low, and there is no distending pain, it belongs to Qi Deficiency, where scant blood causes sluggish flow, constituting a Deficiency disease. If the color is purple, blood volume is high, and abdominal distending pain exists, it belongs to Qi Excess, where abundant blood causes stasis, constituting an Excess disease.