丹溪先生云∶痘疮倒陷，因真气虚，而毒瓦斯不能尽出者，用黄 、人参、紫草酒制治之。若将成就之际，却淡色者，
属血虚，用当归、川芎之类，或加红花、紫草。属热毒者，用升麻、芩、连、梗、翘之类，甚者用犀角屑，大解痘毒。
窃谓前症若热毒方出，忽被风寒闭塞，肌窍血脉不行，身体作痛，或四肢微厥， 点不长，或变青紫黑色者，此为倒靥。
若胃气虚弱，不能补接荣卫，出而复没者，谓之陷伏。误用解毒之药，必致陷塌。若喜热饮食，手足并冷者，乃脾胃亏
损，阳气虚寒之症，宜用辛热之剂补之。喜冷冻饮料食，手足并热，乃阳气实热之症，宜用苦寒之剂泻之。外感风寒者，温
散之。毒入腹者，分利之。阳气虚者，温补之。外寒触犯者，熏解之。陈宿州先生用十二味异功散，以预保脾土于未
败之先，实发前人之未发，开万世之蒙聩也。
一小儿痘将愈，忽黑陷，余谓气血虚。用紫草散加人参、当归，又用参 托里散而愈。
一小儿将愈而倒靥，切牙寒战，手足并冷，饮沸汤而不知热，用十二味异功散，一剂诸症顿退，却用五味异功散，
倍用参术数剂而愈。
一小儿痘，饮食多而作吐，服枳术丸，色黑将陷，用五味异功散加干姜，二剂贯浆而靥。
一男子发热昏愦，数日发红点，用快 汤、托里散，贯浆将靥，忽发热恶寒，疮黑倒靥，手足并冷，口渴饮汤，此
阳气虚寒也，用独参汤四剂，诸症渐愈而靥。
一小儿兼呕，手足并冷，余谓脾气虚寒，欲用十二味异功散，不信，另用杂药而殁。
成都方士禹太和，治痘疮黑陷垂死者，用壁间喜蛛，如黄豆大者一枚，擂烂。一岁儿用雄黄一分；二岁，二分；十
岁者用一钱，入蜘蛛内研匀，用好烧酒调服。愚意此即木香散、异功散之类也。若因阳气虚寒，不能荣运周身，以致四
肢逆冷，腹胀唇青黑陷者，宜用烧酒。若因元气虚弱，色白隐于肌肤，而不能起发者，宜用陈酒，亦不可拘泥于烧酒
也。若小儿未及周岁，或儿大者。宜酌量与之，不可拘于杯许也。又有一等症，气血俱虚者，或色淡红，不光泽，不起
发，或惊悸切牙者，加紫草、红花以用之。
七味白术散（方见发热属阴阳）
十一味木香散
十二味异功散（二方见痘灰白色）
丹溪先生曾说：痘疮出现倒陷，是因为真气虚弱，导致毒邪不能完全透发出来，治疗应用黄芪、人参、紫草（经酒制）来调理。如果痘疮即将成熟时，颜色却淡白，这属于血虚，应用当归、川芎等药物，或者加入红花、紫草。若属于热毒证，应用升麻、黄芩、黄连、桔梗、连翘等药物，病情严重的用犀角屑，以大力解除痘毒。
我私下认为，前述病症如果是热毒刚刚发出，忽然被风寒闭塞，导致肌表毛孔和血脉运行不畅，身体疼痛，或者四肢轻微厥冷，痘点不长，或者变为青紫黑色，这叫作“倒靥”。如果胃气虚弱，不能补充和接续营卫之气，痘疹发出后又隐没下去的，叫作“陷伏”。此时如果误用解毒的药物，必然会导致痘疮塌陷。如果患者喜欢热饮食，手足都冰冷，这是脾胃亏损，阳气虚寒的病症，适宜用辛热的药剂来补益。如果患者喜欢冷冻饮料食物，手足都发热，这是阳气实热的病症，适宜用苦寒的药剂来泻火。外感风寒的，用温散的方法治疗。毒邪入腹的，用分利的方法治疗。阳气虚弱的，用温补的方法治疗。外寒触犯的，用熏蒸解表的方法治疗。陈宿州先生使用十二味异功散，在脾土败坏之前预先保护它，这确实是发挥了前人的未发之论，开启了万世的蒙昧与昏聩啊。
有一个小儿痘疮将要痊愈时，忽然变黑下陷，我认为这是气血虚弱。用了紫草散加人参、当归，又用了参芪托里散而痊愈。
有一个小儿痘疮将愈时出现倒靥，咬牙寒战，手足都冰冷，喝滚烫的水却不知道烫，用了十二味异功散，一剂药后各种症状立刻消退，后来改用五味异功散，加倍使用人参、白术，服用数剂后痊愈。
有一个小儿出痘，饮食多却呕吐，服用了枳术丸，痘色变黑将要下陷，用了五味异功散加干姜，两剂药后痘浆充盈并结痂。
有一个男子发热神志昏乱，几天后发红点，用了快斑汤、托里散，痘浆充盈将要结痂时，忽然发热恶寒，疮口变黑倒陷，手足都冰冷，口渴想喝热水，这是阳气虚寒，用了独参汤四剂，各种症状逐渐好转并结痂。
有一个小儿兼有呕吐，手足都冰冷，我认为这是脾气虚寒，想用十二味异功散，家属不信，另用杂药治疗，结果孩子死亡。
成都方士禹太和，治疗痘疮黑陷濒临死亡的病人，用墙壁间喜欢的蜘蛛，如黄豆大的一只，捣烂。一岁婴儿用雄黄一分；两岁用二分；十岁用一钱，放入蜘蛛内研匀，用好烧酒调服。我的意思是，这也就是木香散、异功散之类的道理。如果是因阳气虚寒，不能荣养运化周身，以致四肢逆冷，腹胀唇青黑陷的，适宜用烧酒。如果是因元气虚弱，颜色白隐于肌肤，而不能起发的，适宜用陈年酒，也不可拘泥于只用烧酒。如果是未满周岁的小儿，或者年龄较大的儿童，应酌情给予，不可拘泥于一杯的量。又有一种情况，气血都虚弱的，或者颜色淡红，不光泽，不起发，或者惊悸咬牙的，加入紫草、红花来使用。
Mr. Danxi once said: When smallpox lesions invert and sink, it is due to the deficiency of true qi, preventing the pathogenic toxins from being fully expelled. Treatment should involve Huangqi (Astragali Radix), Renshen (Ginseng Radix et Rhizoma), and Zicao (Arnebiae Radix) processed with wine. If the lesions are about to mature but appear pale, this belongs to blood deficiency; use Danggui (Angelicae Sinensis Radix), Chuanxiong (Ligustici Chuanxiong Rhizoma), etc., or add Honghua (Carthami Flos) and Zicao. If it belongs to heat-toxin syndrome, use Shengma (Cimicifugae Rhizoma), Huangqin (Scutellariae Radix), Lianlian (Coptidis Rhizoma), Jiegeng (Platycodonis Radix), and Lianqiao (Forsythiae Fructus). For severe cases, Xijiaoxie (Rhinocerotis Cornu) is used to strongly resolve the smallpox toxin.
I privately believe that if the aforementioned condition involves heat-toxin just emerging, suddenly blocked by wind-cold, causing the skin pores and blood vessels to stagnate, resulting in body pain or slight coldness of the four limbs, where the spots do not grow or turn cyanotic/purple/black, this is called "Dao Ye" (Inverted Smallpox). If stomach qi is weak and cannot supplement and connect Ying and Wei (Nutritive and Defensive Qi), causing the eruption to emerge and then disappear, it is called "Xian Fu" (Sunken Smallpox). Misusing detoxifying herbs at this stage will inevitably lead to collapse. If the patient prefers hot food and drinks, with cold hands and feet, this is a syndrome of spleen-stomach damage and yang-deficiency cold; it is suitable to use acrid-hot formulas to tonify. If the patient prefers cold food and drinks, with hot hands and feet, this is a syndrome of excess-heat in yang; it is suitable to use bitter-cold formulas to drain. For external wind-cold, use warm-dispersing methods. For toxins entering the abdomen, use separating-and-draining methods. For deficient yang, use warming-tonifying methods. For invasion by external cold, use fumigation and resolution methods. Mr. Chen Suzhou used Twelve-Ingredient Yigong San (Twelve-Ingredient Extraordinary Efficacy Powder) to protect the spleen-earth before its collapse, truly expounding upon what predecessors had not yet revealed, and enlightening generations of ignorance.
One child’s smallpox was nearly healed when it suddenly turned black and sank. I diagnosed it as qi and blood deficiency. It was cured using Zicao San (Arnebia Powder) added with Renshen and Danggui, followed by Shenqi Tuoli San (Ginseng and Astragalus Supporting Interior Powder).
Another child, whose smallpox was nearing healing, developed inverted lesions, teeth-chattering, shivering, and cold hands and feet. The child drank boiling water without feeling the heat. After one dose of Twelve-Ingredient Yigong San, all symptoms subsided instantly. Subsequently, Five-Ingredient Yigong San (Five-Ingredient Extraordinary Efficacy Powder) was used, with doubled amounts of Renshen and Baizhu (Atractylodis Macrocephalae Rhizoma), administered over several doses until recovery.
A child with smallpox ate much but vomited. After taking Zhizhu Wan (Immature Bitter Orange and Atractylodes Pill), the lesions turned black and were about to sink. Five-Ingredient Yigong San added with Ganjiang (Zingiberis Rhizoma) was used. After two doses, the lesions filled with pus and formed scabs.
A man suffered from fever and confusion. Red spots appeared after several days. Kuai Ban Tang (Rapid Rash Decoction) and Tuoli San were used. As the lesions filled with pus and were about to scab, he suddenly developed fever and aversion to cold, with lesions turning black and inverting, accompanied by cold hands and feet and thirst for hot water. This indicated yang-deficiency cold. Four doses of Dushen Tang (Single Ginseng Decoction) were administered, leading to gradual improvement and scabbing.
A child presented with vomiting and cold hands and feet. I diagnosed spleen-qi deficiency and cold, intending to use Twelve-Ingredient Yigong San. The family did not believe me and used miscellaneous medicines instead, resulting in the child's death.
Yu Taihe, a practitioner from Chengdu, treated patients with black-sunken smallpox near death using a spider found on walls, about the size of a soybean, mashed. For a one-year-old infant, 1 fen of Xionghuang (Realgar); for a two-year-old, 2 fen; for a ten-year-old, 1 qian. These were mixed into the spider paste and taken with good burning liquor (baijiu). My understanding is that this is similar to Muxiang San (Costus Powder) and Yigong San. If caused by yang-deficiency cold, failing to nourish and circulate the body, leading to cold extremities, abdominal distension, blue-black lips, and sinking lesions, burning liquor is suitable. If caused by yuan-qi (Original Qi) weakness, with pale color hidden in the skin and failure to erupt, aged wine is suitable; one should not be rigidly confined to burning liquor. For infants under one year old or older children, dosage should be adjusted appropriately, not restricted to a cupful. In another type of case involving dual deficiency of qi and blood, or pale-red, dull, non-erupting lesions, or palpitations and teeth-chattering, Zicao and Honghua should be added.
Qiwei Baizhu San (Seven-Ingredient White Atractylodes Powder) (Formula see Fever Belonging to Yin and Yang)
Shiyiwei Muxiang San (Eleven-Ingredient Costus Powder)
Shierwei Yigong San (Twelve-Ingredient Extraordinary Efficacy Powder) (Both formulas see Grayish-White Smallpox)