Danyu said that among all diseases, Lao Zheng (chronic consumptive disease) is the most difficult to treat. This is largely because in their prime years, individuals fail to preserve their vitality and indulge in alcohol and sexual activity without rest day and night, suddenly causing damage.

When Zhen Yuan (the fundamental vital energy of the human body) is depleted and essence and fluid are exhausted, symptoms such as hematemesis (vomiting blood), expectoration of phlegm, bone-steaming tidal fever (a sensation of heat radiating from the deep marrow), generalized fever, pale complexion with malar flush, dry mouth and throat, nocturnal sweating, spermatorrhea, cough, and lethargy occur. This condition is referred to as "Fire Excess and Metal Deficiency" (insufficiency of Kidney Water leading to weakness of Lung Metal). Severe cases result in death within half a year, while mild cases may lead to death within one year. For those who are good at self-care and have a normal appetite, if medication is taken when only one or two initial symptoms appear, the disease can certainly be cured. However, if negligence persists for a long time, leading to extreme emaciation and depletion of Zhen Yuan, medical treatment administered thereafter would be ineffective even if Lu Bian (referring to the legendary physician Bian Que) were resurrected; this is truly lamentable.

Master Ge stated that Chuan Shi (an infectious chronic consumptive disease) often involves parasites. It is extremely harmful; although it is pitiable for one person to suffer from it, it is even more so when transmitted through close care or intimate contact over a long period due to exposure to its malignant qi. It is named Chuan Shi, also known as Si Shi, Fei Shi, Dun Shi, [missing character] Shi, Shi Zhu, and Gui Zhu, names that describe its transmissive nature and unpredictable changes akin to malaria. Nevertheless, no case arises without prior constitutional weakness and damage to the Heart and Kidneys. Initially affecting one person due to lack of caution, it can then spread to dozens of people, and in extreme cases, wipe out an entire family. This disease is particularly vile because prolonged stagnation generates abnormal entities that consume the essence of internal organs, producing various strange substances, which is indeed terrifying. Thus, damage to the Liver and Gallbladder produces hairy insects, such as Ci Wa KT (specific insect types mentioned in the text), which consume intestinal membranes; damage to the Heart and Small Intestine produces feathered insects, resembling moths, mosquitoes, or birds, which consume blood vessels; damage to the Spleen and Stomach produces [missing character] worms, resembling infants or earthworms, which consume muscles; damage to the Lungs and Large Intestine produces shelled insects, resembling turtles, crabs, shrimp, or crayfish, which consume skin fat; and damage to the Kidneys and Bladder produces scaled insects, resembling fish, dragons, or pangolins, which consume bones.

Dai Yun stated that this represents extreme Yin deficiency with pathological phlegm and blood, often involving parasites. One cannot deny the existence of parasites in Chuan Shi. If alternating chills and fever persist, accompanied by chronic cough with hemoptysis, progressive emaciation, hypochondriac pain, and gradual development of hemiplegia, the prognosis is poor.

Wang Jiezhai stated that men under the age of twenty who overindulge in sexual activity will inevitably damage their essence and blood, leading to diseases characterized by Yin deficiency and hyperactive fire. Symptoms include nocturnal sweating during sleep, afternoon fever, cough, fatigue, weakness, reduced appetite, and in severe cases, blood-streaked sputum, hemoptysis, hematemesis, epistaxis, generalized fever, a deep and rapid pulse, and muscle wasting. This is called Lao Zhai (consumptive disease, typically referring to tuberculosis), which is the most difficult to treat. Mild cases require dozens of doses of medicine, while severe cases may take a year to resolve. However, the patient must have strong willpower, abstain completely from sexual intercourse, eliminate delusional thoughts, avoid anger, and regulate diet to nourish the root. Otherwise, even the best medicines will be useless. Early treatment is effective; however, once emaciation sets in, the patient becomes bedridden, and the pulse becomes deep and rapid, treatment becomes difficult. Generally, this disease involves internal fire consuming Yin blood, resulting in frequent constipation. Although diet should be regulated to prevent diarrhea, if the Stomach Qi fails further, leading to loose stools or cold-type diarrhea, cold-natured herbs are difficult to use.