四十九难曰∶有正经自病，有五邪所伤，何以别之？然∶忧愁思虑则伤心，形寒饮冷则
伤肺；恚怒气逆上而不下则伤肝；饮食劳倦则伤脾；久坐湿地，强力入水则伤肾。是正经之
自病也。
何谓五邪？然∶有中风，有伤暑，有饮食劳倦，有伤寒，有中湿。此之谓五邪。
假令心病，何以知中风得之？然∶其色当赤。何以言之？肝主色，自入为青，入心为赤，入脾
为黄，入肺为白，入肾为黑。肝为心邪，故知当赤色。其病身热、胁下满痛。其脉浮大而弦。
何以知伤暑得之？然∶当恶臭。何以言之？心主臭，自入为焦臭，入脾为香臭，入肝为臊臭，
入肾为腐臭，入肺为腥臭。故知心病伤暑得之，当恶臭，其病身热而烦，心痛。其脉浮大而散。
何以知饮食劳倦得之？然∶当喜苦味也。虚为不欲食，实为欲食。何以言之？脾主味，入肝为酸，
入心为苦，入肺为辛，入肾为咸，自入为甘。故知脾邪入心，为喜苦味也。其病身热而体重嗜卧，四
肢不收。其脉浮大而缓。
何以知伤寒得之？然∶当谵言妄语。何以言之？肺主声，入肝为呼，入心为言，入脾为歌，
入肾为呻，自入为哭，故知肺邪入心，为谵言妄语也。其病身热，洒洒恶寒，甚则喘咳。其脉浮大而涩。
何以知中湿得之？然∶当喜汗出不可止。何以言之？肾主湿，入肝为泣，入心为汗，入脾为涎，
入肺为涕，自入为唾。故知肾邪入心，为汗出不可止也。其病身热而小腹痛，足胫寒而逆。其脉沉濡而
大。此五邪之法也。
第四十九难说：有正经自病，有五邪所伤，如何区分它们？回答说：忧愁思虑会损伤心脏，形体受寒或饮用冷物会损伤肺脏；愤怒导致气逆上冲而不能下行会损伤肝脏；饮食不节和过度劳累会损伤脾脏；久坐潮湿之地，或强力涉水会损伤肾脏。这就是正经的自病。
什么是五邪？回答说：有中风，有伤暑，有饮食劳倦，有伤寒，有中湿。这就叫做五邪。
假如是心脏患病，如何知道是由中风引起的呢？回答说：面色应当发红。为什么这样说？肝主五色，青色入肝为本色，赤色入心，黄色入脾，白色入肺，黑色入肾。肝作为心的邪气（木生火，肝木为心火之母，此处指母病及子或相乘关系，原文意指肝之邪气传入心），所以知道面色当红。其病症表现为身体发热、胁下胀满疼痛。其脉象浮大而弦。
如何知道是由伤暑引起的呢？回答说：应当厌恶臭味。为什么这样说？心主五臭，焦臭味入心为本色，香味入脾，臊味入肝，腐臭味入肾，腥臭味入肺。所以知道心脏患病由伤暑引起，应当厌恶臭味，其病症表现为身体发热且心烦，心痛。其脉象浮大而散。
如何知道是由饮食劳倦引起的呢？回答说：应当喜欢苦味。虚证则不想进食，实证则想进食。为什么这样说？脾主五味，酸味入肝，苦味入心，辛味入肺，咸味入肾，甘味入脾为本色。所以知道脾之邪气传入心，表现为喜欢苦味。其病症表现为身体发热、身体沉重、嗜睡、四肢无力收持。其脉象浮大而缓。
如何知道是由伤寒引起的呢？回答说：应当出现胡言乱语。为什么这样说？肺主五声，呼号声入肝，言语声入心，歌声入脾，呻吟声入肾，哭声入肺为本色，所以知道肺之邪气传入心，表现为胡言乱语。其病症表现为身体发热，淅淅恶寒，严重时气喘咳嗽。其脉象浮大而涩。
如何知道是由中湿引起的呢？回答说：应当喜欢汗出不止。为什么这样说？肾主五液，泪入肝，汗入心，涎入脾，涕入肺，唾入肾为本色，所以知道肾之邪气传入心，表现为汗出不止。其病症表现为身体发热、小腹痛，足胫寒冷且逆冷。其脉象沉濡而大。这就是辨别五邪的方法。
Difficulty 49 states: There are diseases originating from the regular meridians themselves (Zhengjing Zibing) and those caused by the Five Evils (Wu Xie). How can they be distinguished? The answer is: Worry and overthinking damage the Heart; exposure to cold and consumption of cold drinks damage the Lungs; anger causing Qi rebellion upward without descending damages the Liver; improper diet and overexertion damage the Spleen; sitting long in damp places or forcing oneself into water damages the Kidneys. These constitute the diseases of the regular meridians themselves.
What are the Five Evils? The answer is: Wind-stroke (Zhong Feng), Summerheat injury (Shang Shu), Diet and overexertion, Cold injury (Shang Han), and Dampness invasion (Zhong Shi). This is referred to as the Five Evils.
Suppose a Heart disease occurs; how do we know it is caused by Wind-stroke? The answer is: The complexion should be red. Why? The Liver governs colors. Green enters the Liver (its own organ), Red enters the Heart, Yellow enters the Spleen, White enters the Lungs, and Black enters the Kidneys. Since the Liver acts as the evil for the Heart (Wood generating Fire, implying the pathogenic factor from the mother organ affecting the child), we know the complexion will be red. The symptoms include body heat, fullness and pain under the hypochondrium. The pulse is floating, large, and wiry (Xian).
How do we know it is caused by Summerheat injury? The answer is: There should be aversion to odors. Why? The Heart governs odors. Burnt odor enters the Heart (its own organ), Fragrant odor enters the Spleen, Pungent/Fishy odor enters the Liver, Rotten odor enters the Kidneys, and Fishy odor enters the Lungs. Therefore, knowing that the Heart disease is caused by Summerheat, there should be an aversion to odors. The symptoms include body heat, vexation, and heart pain. The pulse is floating, large, and scattered (San).
How do we know it is caused by diet and overexertion? The answer is: There should be a preference for bitter taste. Deficiency leads to lack of appetite, while Excess leads to desire for food. Why? The Spleen governs tastes. Sour taste enters the Liver, Bitter taste enters the Heart, Acrid/Pungent taste enters the Lungs, Salty taste enters the Kidneys, and Sweet taste enters the Spleen (its own organ). Therefore, knowing that the Spleen's evil enters the Heart, there is a preference for bitter taste. The symptoms include body heat, heavy body, drowsiness, and limbs that cannot be gathered or controlled. The pulse is floating, large, and slow (Huan).
How do we know it is caused by Cold injury? The answer is: There should be delirious speech and妄语 (confabulation/nonsense). Why? The Lungs govern sounds. Crying sound enters the Lungs (its own organ), Calling out enters the Liver, Speaking enters the Heart, Singing enters the Spleen, Moaning enters the Kidneys. Therefore, knowing that the Lung's evil enters the Heart, there is delirious speech. The symptoms include body heat, shivering with aversion to cold, and severe cases may involve wheezing and coughing. The pulse is floating, large, and choppy (Se).
How do we know it is caused by Dampness invasion? The answer is: There should be profuse sweating that cannot be stopped. Why? The Kidneys govern fluids. Tears enter the Liver, Sweat enters the Heart, Saliva (thin) enters the Spleen, Nasal mucus enters the Lungs, and Spittle (thick) enters the Kidneys (its own organ). Therefore, knowing that the Kidney's evil enters the Heart, there is unstoppable sweating. The symptoms include body heat, lower abdominal pain, and coldness with reversal in the feet and calves. The pulse is deep, soggy (Ru), and large. This is the method for distinguishing the Five Evils.