用四物汤以治血者，不可不察其宜否之性。○褚氏曰∶喉有窍，咳血杀人；肠有窍，便血杀人。便血犹可治，
咳血不可医。饮溲溺者，百不一死；服寒凉者，百不一生。血虽阴类，运之者其阳和乎？愚谓∶褚氏之说，真
元理之法，不可不知。至若溲溺之用，则但于邪热上炎者，借以降火，是诚善矣。其若伤在脾胃，或阳虚阴
胜等证，则非所宜，勿谓百不一死可概用也。（张景岳）
书云∶气有生血之功，补血不如补气。此言阴络伤，血内溢，血虚无火之证，非言阳络伤，血外溢，血虚
有火之证也。夫曰阴络伤，血内溢，言下泄、下脱之血也；阳络伤，血外溢，言上冲
咳血、吐血、鼻衄、牙衄之血也。夫阴络所伤之血，血去则火亦去，此血虚无火者也；阳络所伤之血，血去则
使用四物汤来治疗血证，不能不考察其是否适宜。○褚氏说：咽喉有孔窍，咳血会致死；肠道有孔窍，便血也会致死。便血尚且可以治疗，咳血则难以医治。饮用尿液的人，一百个中不一定有一个死亡；服用寒凉药物的人，一百个中没有一个能存活。血液虽然属于阴类，但推动血液运行的难道是阳气吗？我认为：褚氏的说法，确实是符合元气的真理法则，不可不知道。至于使用尿液的方法，只是对于邪热上炎的情况，借以降火，这确实很好。如果是脾胃受损，或者阳虚阴盛等证候，就不适宜了，不要认为“百不一死”就可以一概使用。（张景岳）
书上说：气有生血的功效，补血不如补气。这句话讲的是阴络受伤，血液内溢，血虚无火的证候，并不是讲阳络受伤，血液外溢，血虚有火的证候。所谓阴络受伤，血液内溢，指的是下部泄出、下部脱失的血液；阳络受伤，血液外溢，指的是向上冲逆导致的咳血、吐血、鼻衄（鼻出血）、牙衄（牙龈出血）的血液。阴络所伤的血液，血去除了火也随之而去，这是血虚无火的情况；阳络所伤的血液，血去除了……
When using Siwu Tang (Four Substances Decoction) to treat blood disorders, one must carefully examine whether it is appropriate. ○ Chu Shi stated: The throat has orifices; hemoptysis (coughing up blood) can be fatal; the intestines have orifices; hematochezia (blood in stool) can also be fatal. Hematochezia is still treatable, whereas hemoptysis is difficult to cure. Those who drink urine may survive in more than one out of a hundred cases; those who take cold-cooling herbs rarely survive. Although blood belongs to Yin, is it not Yang that facilitates its movement? I believe that Chu Shi’s statement indeed reflects the fundamental principles of Yuan Qi (Original Qi), which should not be ignored. As for the use of urine, it is indeed beneficial for reducing fire by borrowing its descending property when pathogenic heat flares upward. However, if the injury involves the Spleen and Stomach, or if there are syndromes such as Yang deficiency with Yin excess, it is not suitable. One should not assume that because "one out of a hundred survives," it can be universally applied. (Zhang Jingyue)
Books state: Qi has the merit of generating blood; tonifying Qi is superior to nourishing Blood. This statement refers to injuries of the Yin collaterals causing internal bleeding and blood deficiency without fire, rather than injuries of the Yang collaterals causing external bleeding and blood deficiency with fire. By "Yin collateral injury and internal bleeding," it refers to blood leaking or escaping from below; by "Yang collateral injury and external bleeding," it refers to blood rushing upward, manifesting as hemoptysis, hematemesis (vomiting blood), epistaxis (nosebleed), and gingival bleeding. In cases of blood injured by Yin collaterals, once the blood is lost, the fire also dissipates; this constitutes blood deficiency without fire. In cases of blood injured by Yang collaterals, once the blood is lost...