（即呕血。旧分无声曰吐，有声曰呕，不必。）
吐由口出，古人谓是胃腑之血。张景岳则谓出于口者，有咽与喉之异。喉为肺
之上窍，而兼总五脏之清道，故诸脏之血，皆得从清道以出于喉，不独肺也。咽为
胃之上窍，而兼总六腑之浊道，故诸腑之血，亦皆得由浊道以出于咽，不独胃也。
五脏之气皆禀于胃，则五脏之病亦皆及于胃。如怒则气逆而呕血，肝病也。欲火
上炎而呕血，肾病也。而其血皆由胃脘以出，则是出于喉者止五脏之血，而出于咽
者，不只六腑之血矣。按景岳之说甚是，然何以别之？大抵由肝肾而出者，往往倾
盆而来，如潮之涌，此雷龙之火暴发乘胃所致。肝、肾、胃血俱出，彼时喘息不定，
面如醉酒，心神烦乱，少刻火退神清，面白气平，血乃渐止。若胃火自病，其势不
甚暴烈，所出必不若是之多也。凡血色初吐鲜红而散，少停一、二时再吐，则略紫
而凝，久而又吐，则黑而结块。若吐血不停，则初吐者为上焦近血，色鲜红。后出
者为中下焦远血，其色深红。吐后未尽余血，色淡或糖色，或粉红色。
火刑金而肺叶干皱则痒，痒则咳，此不必有痰，故名干咳。咳多则肺络伤，而
血出矣。嗽则兼有痰，痰中带有血线，亦肺络之血也。其证有轻重，但热壅于肺者
轻，清火自愈。久嗽肺损者重，保肺为主，阿胶为君，白芨、苡仁、生地、甘草、
枳梗、橘红、贝母为丸，噙化。又须看痰色如玛瑙成块者，出胃口，易治。若
一丝一点，从肺脏中来，肺少血，为火所逼，虽少亦出，渐至肺枯成痨，难治。咳出
白血必死。（血色浅红，似肉似肺者是。）脉弦气喘，声嘶咽痛，不治。
（吐血即呕血。旧时区分无声的称为吐，有声的称为呕，这种区分并无必要。）
血液从口中吐出，古人认为是胃腑的血液。张景岳则认为从口而出的，有咽喉与喉部的区别。喉部是肺的上窍，并且兼管五脏的清道，所以各脏器的血液，都能通过清道从喉部出来，不单单是肺。咽部是胃的上窍，并且兼管六腑的浊道，所以各腑器的血液，也能通过浊道从咽部出来，不单单是胃。
五脏的气都禀受于胃，那么五脏的疾病也都会波及到胃。例如发怒导致气逆而呕血，这是肝病的表现。相火上炎而呕血，这是肾病的表现。而这些血液都是从胃脘处出来的，那么从喉部出来的只是五脏的血液，而从咽部出来的，就不只限于六腑的血液了。考察张景岳的说法非常正确，然而如何辨别呢？大致由肝肾而出来的，往往像倾盆大雨一样涌出，如潮水般汹涌，这是雷龙之火暴发乘袭胃腑所致。肝、肾、胃的血液一起涌出，此时喘息不定，面色如醉酒状，心神烦乱，片刻后火退神清，面色苍白气息平稳，血液才逐渐停止。如果是胃火自病，其势头不那么暴烈，所出的血量也不会像那样多。凡是血色初吐时鲜红且散漫，稍停一两个时辰再吐，则略微紫暗而凝结，时间久了再吐，则黑而结成块状。如果吐血不停止，那么初吐的是上焦近处的血，颜色鲜红。后来出来的是中下焦远处的血，颜色深红。吐完后未尽的余血，颜色淡或呈糖色，或粉红色。
火克金导致肺叶干燥起皱则发痒，痒则咳嗽，这不一定有痰，所以名叫干咳。咳嗽多了则肺络受伤，血液就会流出。嗽则兼有痰，痰中带有线状的血丝，这也是肺络的血液。这种病症有轻重之分，但若是热邪壅塞于肺的较轻，清热泻火即可自愈。久咳导致肺损伤的较重，以保肺为主，用阿胶作为君药，白芨、苡仁、生地、甘草、枳梗、橘红、贝母制成丸剂，含化服用。还需要观察痰的颜色，如果是像玛瑙一样成块的，是从胃口出来的，容易治疗。若是一丝一点，从肺脏中来的，说明肺中少血，被火邪逼迫，即使量少也会流出，逐渐导致肺枯形成劳损，难以治疗。咳出白血必定死亡。（血色浅红，似肉似肺的就是。）脉象弦急气喘，声音嘶哑咽喉疼痛，属于不治之症。
(Tu xue, hematemesis, is equivalent to ou xue, vomiting blood. The old distinction that silent expulsion is called "tu" and noisy expulsion is called "ou" is unnecessary.)
Blood expelled from the mouth was traditionally considered to be blood from the Wei Fu (Stomach Organ). Zhang Jingyue argued that what comes out of the mouth differs between the Yan (Pharynx) and the Hou (Larynx/Throat). The Hou is the upper orifice of the Fei Zang (Lung Organ) and serves as the general pathway for the clear qi of the five Zang organs; therefore, blood from all organs can exit through the Hou via this clear pathway, not just from the Lung. The Yan is the upper orifice of the Stomach and serves as the general pathway for the turbid qi of the six Fu organs; thus, blood from all organs can also exit through the Yan via this turbid pathway, not just from the Stomach.
The Qi of the five Zang organs is derived from the Stomach; consequently, diseases of the five Zang organs will also affect the Stomach. For instance, anger causing Qi rebellion leading to hematemesis is a manifestation of Gan Bing (Liver Disease). Ministerial Fire flaring upward causing hematemesis is a manifestation of Shen Bing (Kidney Disease). Since this blood all exits from the Wei Wan (Epigastrium), it follows that blood exiting via the Hou belongs only to the five Zang organs, whereas blood exiting via the Yan includes not only the six Fu organs but potentially others.
Examining Zhang Jingyue’s theory, it is highly accurate, yet how should one differentiate them? Generally, when blood originates from the Gan and Shen, it often pours forth like a bucket being overturned, surging like tidal waves. This is caused by the sudden outbreak of Lei Long Zhi Huo (Thunder Dragon Fire) attacking the Stomach. Blood from the Liver, Kidney, and Stomach all erupt simultaneously; at this moment, there is irregular breathing, a face resembling drunkenness, and mental restlessness. After a short while, as the fire subsides and clarity returns, the complexion becomes pale and breathing stabilizes, and the bleeding gradually stops. If the condition is due to Wei Huo (Stomach Fire) arising independently, the intensity is not as violent, and the volume of blood lost will not be as excessive.
Regarding the color of the blood: initially vomited blood is bright red and loose. After a pause of one or two hours, if vomiting recurs, the blood becomes slightly purplish and coagulated. If vomiting continues over a long period, the blood turns black and forms clots. If hematemesis persists, the first blood expelled comes from the Upper Jiao (Upper Burner) and is near in location, appearing bright red. Subsequent blood comes from the Middle and Lower Jiao, distant in location, appearing dark red. The residual blood remaining after vomiting ceases appears pale, sugar-colored, or pinkish-red.
When Fire destroys Metal, the Fei Ye (Lung Lobes) become dry and wrinkled, causing itching. Itching leads to Ke Sou (Coughing); this may occur without phlegm, hence it is named Gan Ke (Dry Cough). Frequent coughing damages the Fei Luo (Lung Collaterals), causing blood to emerge. Sou (cough with phlegm) involves phlegm containing thread-like streaks of blood, which is also blood from the Lung Collaterals. These conditions vary in severity. If the syndrome is caused by Heat obstruction in the Lung, it is mild and will heal spontaneously with Qing Huo (Clearing Fire). If prolonged coughing causes Lung damage, it is severe; the treatment principle focuses on Bao Fei (Protecting the Lung), using E Jiao (Donkey-Hide Gelatin) as the Jun Yao (Sovereign Drug), combined with Bai Ji (Bletilla Rhizome), Yi Ren (Coix Seed), Sheng Di Huang (Rehmannia Root), Gan Cao (Licorice Root), Zhi Geng (Platycodon Root), Ju Hong (Tangerine Peel), and Bei Mu (Fritillaria Bulb) prepared into pills for holding in the mouth to dissolve.
One must also observe the sputum. If the sputum resembles agate in chunks and originates from the Wei Kou (Stomach opening), it is easy to treat. If it is merely trace amounts originating from within the Fei Zang (Lung Organ), it indicates Lung Yin deficiency with insufficient blood, forced out by Fire. Even small amounts will appear, gradually leading to Lung exhaustion and forming Lao Bing (Consumption/Tuberculosis), which is difficult to treat. Coughing up white blood guarantees death. (White blood refers to blood that is pale red, resembling flesh or lung tissue.) A Xian Mai (Wiry Pulse) with Qi Chuan (Asthma/Dyspnea), Hoarse Voice (Sheng Si), and Yan Tong (Sore Throat) indicates an untreatable condition.