小儿麻痘时，未服寒凉而后患牙疳者轻，则东垣清胃散为妙。若龈腐黑焦，气息秽浊，确系实火者，可用芦
荟消疳饮，火盛者加石膏、川黄连照本科治法或能获效。倘麻痘中清凉已甚，复因俗见痘后必要清凉解毒，于
是愈凉而愈遏，以致水极似火，而牙疳之患作矣。医者犹谓毒未解尽，更进寒凉，甚至破唇穿腮，变为焦黑，延
烂及面，与鼻形恶不堪，惨情己极，此医之罪也。
凡牙疳为寒凉过度而齿落，未经穿腮者，须用冯氏全真一气主之。譬如阴湿霾晦之处。须得太阳照临，始能
干燥，此一定之理也。奈今时医家谁能得此三味，亦断不能作此治法，是故流毒日深，何异投井下石，牢不可破！
因此夭枉者，不可胜数已。若牙疳初起，血出色淡，牙床不红紫而腐，不发热者，此虚候也。苦寒之品，毫不可
犯，即用玉女煎治之，但石膏不可用重。如下焦阴火发为牙疳者，六味加麦冬、知母，或玉女煎去石膏加丹皮、
石斛。吹药用口疳散、神功丹或圣功丹皆可，惟穿唇破腮者，只用赤霜散妙。又有病后牙疳，当理脾者，四君加
归芍主之。
During the eruption of smallpox or measles in children, if cold-natured medicines were not taken previously and gingival gangrene (Yagan, a disease characterized by gum necrosis) subsequently occurs, the condition is mild; in such cases, Dongyuan Qingwei San (Stomach-Clearing Powder) is excellent. If the gums are rotten, blackened, and scorched, with foul breath, indicating a true excess-heat syndrome, Luhui Xiaogang Yin (Aloe Gangrene-Resolving Decoction) may be used. If the fire-heat is vigorous, Shigao (Gypsum Fibrosum) and Chuan Huanglian (Coptidis Rhizoma) should be added, following the treatment methods outlined in this section, which may yield efficacy. However, if cooling medicines have been excessively used during the treatment of smallpox or measles, compounded by the common misconception that post-smallpox care requires cooling and detoxification, the continuous use of cold medicines further suppresses the pathogen. This leads to "water extreme resembling fire" (extreme yin-cold forcing yang outward, presenting as false heat), thereby triggering gingival gangrene. Physicians still believe the toxin is not fully resolved and administer more cold medicines, resulting in cracked lips and perforated cheeks, turning black and scorched, with ulceration spreading to the face and deforming the nose. The tragic state is extreme; this is the fault of the physician.
For gingival gangrene caused by excessive cold medicines leading to tooth loss but without cheek perforation, Fengshi Quanzhen Yiqi Tang (Feng's Complete True One-Energy Decoction) must be used as the primary formula. This is akin to a dark, damp, and foggy place: only when illuminated by the sun can it become dry; this is an immutable principle. Yet, how many contemporary physicians possess these three key ingredients [referring to warming and tonifying herbs like Renshen, Baizhu, Fuzi], and they certainly cannot employ this treatment method. Consequently, the harm deepens daily, which is no different from kicking someone while they are down, making the condition intractable. Thus, those who die prematurely are countless. If gingival gangrene begins initially with pale blood color, non-red/non-purple gums that rot without fever, it is a deficiency syndrome. Bitter-cold substances must not be touched at all; instead, Yupu Jian (Jade Woman Decoction) should be used immediately, but Shigao (Gypsum Fibrosum) should not be used in heavy doses. If lower-jiao deficient fire flares up causing gingival gangrene, Liuwei Dihuang Wan (Six-Ingredient Rehmannia Pill) plus Maidong (Ophiopogonis Radix) and Zhimu (Anemarrhenae Rhizoma) may be used, or Yupu Jian minus Shigao plus Mudanpi (Moutan Cortex) and Shihu (Dendrobii Caulis). For external application, Kougang San (Oral Gangrene Powder), Shengong Dan (Divine Merit Pellet), or Shenggong Dan (Holy Merit Pellet) can be blown into the mouth. Only in cases of lip cracking and cheek perforation is Chishuang San (Red Frost Powder) effective. Furthermore, for gingival gangrene occurring after an illness where spleen regulation is indicated, Sijunzi Tang (Four Gentlemen Decoction) plus Danggui (Angelicae Sinensis Radix) and Shaoyao (Paeoniae Radix) should be used as the main formula.