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)