Whenever a person develops a carbuncle on the back, it is governed by the Foot-Taiyang Bladder Meridian (a major Yang meridian on the posterior aspect of the body, characterized by abundant blood and scarce Qi) and the Du Meridian (which governs the Yang of the whole body). In the initial stage, there must be a white spot in the center, with redness and swelling around the four sides. Gradually, it ulcerates, becoming as large as a plate, with small sores appearing around the periphery containing fluid like rice gruel, sized like millet grains. The patient experiences chills and high fever, along with stiffness and tension throughout the body. One must differentiate through pulse diagnosis: superficial or deep, deficient or excess, exterior or interior. Externally, moxibustion should be applied according to the patient's age in years to intercept the pathogenic toxin and prevent deterioration. Anger must be avoided, alcohol and meat are prohibited, and sexual intercourse is forbidden. If the pus is thick, it indicates solid Yuan Qi; if the pus is thin, it indicates deficient Yuan Qi. Yellowish-red color signifies a favorable prognosis, while black and putrefied tissue signifies an unfavorable one. An open and spreading sore indicates severe toxicity. One must clearly understand the meridians and the abundance or scarcity of blood and Qi, tonifying and supporting deficiency and weakness. If the toxic heat is excessive, one should drain the heat. If pus has formed, urgent puncture is required without delay; delay will cause healthy flesh to rot. The most feared complications are: first, the spread of swelling into the four limbs; second, hardness like stone; third, mental confusion and inability to eat; fourth, perforation of membranes with black putrefaction; fifth, extreme thirst; sixth, internal accumulation of toxin without external manifestation. To treat a back carbuncle, one must know these six essentials, which are the secrets of the ancients. I have recorded them to inform future generations, fearing they might not know this knowledge. Therefore, carbuncles occurring on the chest, back, hypochondrium, ribs, breasts, head, neck, waist, legs, umbilicus, and abdomen are collectively referred to as "Fa" (emission/spreading). The term "Fa" implies largeness. I do not seek novelty but merely emphasize the severity. This serves as the preface.

Lung Carbuncle (Fei Yong)
This carbuncle initially arises from Lung Wei (a chronic wasting disease of the lung), progressing from extreme Wei depletion. The symptom of Lung Carbuncle is coughing up pus and blood from the mouth. The pulse is rapid and excess, with hidden pain in the chest. A tight and rapid Lung pulse indicates that pus has not yet formed. If the pulse is merely rapid, it indicates that pus has already formed, accompanied by foul breath. One should use Xiaofeng San (Wind-Dispersing Powder) mixed with one qian of ash from male hair, taken with clear rice soup. Two doses can cure it. Subsequently, taking Taiyi Gao pills yields excellent results. If wind pathogens invade, it becomes incurable.

Intestinal Carbuncle (Chang Yong)
Whenever a carbuncle forms inside the intestines, symptoms must be verified clearly for accurate diagnosis; blind treatment can be fatal. The disease presents with heaviness in the lower abdomen, pain upon pressure, urination resembling strangury (dysuria), frequent sweating, aversion to cold, skin sensations (such as itching or pain), and tension of the abdominal skin. If swelling is more severe on the left, it is a Small Intestine Carbuncle; if more severe on the right, it is a Large Intestine Carbuncle. The pulse at the Right Cun position is surging and rapid. There may be sores around the umbilicus, pus discharging from the umbilicus, or pus and blood in the stool. Da Huang Mu Dan Tang (Rhubarb and Moutan Decoction) is used for treatment.