On the fourth day of cold damage (Shanghan), the Taiyin meridian is affected. The Taiyin meridian belongs to the Spleen and is the head of the three Yin meridians. Therefore, after the third day, when the pathogenic factors in the Yang meridians have completed their transmission, they enter the Taiyin meridian; thus, it can be treated.

For treating cold damage on the fourth day, where the Taiyin meridian is initially affected, it is appropriate to administer Hengshan San (Hengshan Powder) to induce vomiting.
Ingredients: Hengshan (Dichroae Radix, 3 fen), Gancao (Glycyrrhizae Radix et Rhizoma, 3 fen, raw), Biejia (Testudinis Carapax et Plastrum, 3 fen, coated with vinegar and roasted until yellow, remove the skirt edge), Shigao (Gypsum Fibrosum, 3 fen), Chaihu (Bupleuri Radix, 3 fen, remove seedlings), ZhiMu (Anemarrhenae Rhizoma, 3 fen).
The above ingredients are crushed, sifted, and made into a powder. Take 3 qian per dose. Add one zhong zhan (approx. 200-250ml) of water and ten slices of Danzhuye (Lophatheri Herba). Decoct until reduced to six parts. Strain and take warm at any time. This should induce the vomiting of stubborn phlegm and saliva. Afterwards, Heqi Zhizhong Tang (Heqi Zhizhong Decoction) should be administered to regulate the condition.

For treating the initial infection of the Taiyin meridian, after taking Hengshan San to induce vomiting, it is appropriate to administer Heqi Zhizhong Tang (Heqi Zhizhong Decoction).
Ingredients: Renshen (Ginseng Radix, 0.5 liang, remove rhizome), Huoxiang (Agastaches Herba, 0.5 liang), Baizhu (Atractylodis Macrocephalae Rhizoma, 3 fen), Gancao (Glycyrrhizae Radix et Rhizoma, 1 fen, honey-fried until slightly red, cut into pieces), Ganjiang (Zingiberis Rhizoma, 1 fen, processed until cracked, cut into pieces), Baifuling (Poria, 1 fen), Chenjupi (Citri Reticulatae Pericarpium, 3 fen, soaked in hot water, remove white pith, baked).
The above ingredients are pounded and sieved into a fine powder. Take 2 qian per dose. Add one zhong zhan of water and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to five parts. Remove the ginger, mix with the dregs, and take warm at any time.

For treating cold damage on the fourth day, following vomiting, if there is high fever, headache, body soreness, bitter taste in the mouth, and irritability, it is appropriate to administer Mahuang San (Mahuang Powder).
Ingredients: Mahuang (Ephedrae Herba, 3 fen, remove root and joints), Gegen (Puerariae Lobatae Radix, 3 fen, cut into pieces), Chaihu (Bupleuri Radix, 1 liang, remove seedlings), ZhiMu (Anemarrhenae Rhizoma, 3 fen), ChiShaoyao (Paeoniae Radix Rubra, 1 liang), Zhizi Ren (Gardeniae Semen, 3 fen), Shigao (Gypsum Fibrosum, 1.5 liang), Chenjupi (Citri Reticulatae Pericarpium, 0.5 liang, soaked in hot water, remove white pith, baked), Sheng Dihuang (Rehmanniae Radix, 1 liang).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, presenting with headache, stiffness and pain in the back and shoulders, and stagnation in the heart and abdomen, it is appropriate to administer Chaihu San (Chaihu Powder).
Ingredients: Chaihu (Bupleuri Radix, 1.5 liang, remove seedlings), Chuan Dahuang (Rhei Radix et Rhizoma, 1 liang, cut into pieces, lightly stir-fried), Hengshan (Dichroae Radix, 1.5 liang), Yichen (Artemisiae Scopariae Herba, 1 liang), ZhiMu (Anemarrhenae Rhizoma, 1 liang), ChiShaoyao (Paeoniae Radix Rubra, 1 liang), Gancao (Glycyrrhizae Radix et Rhizoma, 1 liang, honey-fried until slightly red, cut into pieces), Biejia (Testudinis Carapax et Plastrum, 1.5 liang, coated with vinegar and roasted until slightly yellow, remove the skirt edge).
The above ingredients are crushed, sifted, and made into a powder. Take 5 qian per dose. Add one large zhan of Danjiangshui (light fermented grain water). Decoct until reduced to six parts. Strain and take warm at any time. The degree of mild vomiting is the limit; if not vomited, take again.

For treating cold damage on the fourth day, characterized by frequent vomiting and hiccups, headache, and extreme thirst, this syndrome indicates phlegm-stagnation in the Spleen and Stomach. It is appropriate to administer Banxia Tang (Banxia Decoction).
Ingredients: Banxia (Pinelliae Rhizoma, 3 fen, washed seven times in hot water to remove slipperiness), Gancao (Glycyrrhizae Radix et Rhizoma, 0.5 liang, honey-fried until slightly red, cut into pieces), Renshen (Ginseng Radix, 1 liang, remove rhizome), Houpo (Magnoliae Officinalis Cortex, 2 liang, remove rough bark, coated with ginger juice and roasted until fragrant and cooked).
The above ingredients are crushed, sifted, and made into a powder. Take 3 qian per dose. Add one zhong zhan of water and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to five parts. Strain and take slightly warm at any time.

For treating cold damage on the fourth day, with floating and large pulse, fever and aversion to cold, body pain, anhidrosis, and irritability, it is appropriate to administer Da Qinglong Tang (Da Qinglong Decoction).
Ingredients: Mahuang (Ephedrae Herba, 2 liang, remove root and joints), Guixin (Cinnamomi Ramulus, 1 liang), Gancao (Glycyrrhizae Radix et Rhizoma, 1 liang, honey-fried until slightly red, cut into pieces), Shigao (Gypsum Fibrosum, 2 liang), Xingren (Pruni Semen, 30 seeds, soaked in hot water, remove skin and tips, double-kernel, bran-roasted until slightly yellow).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, following improper purgation leading to extreme thirst, and due to excessive intake of cold medicines causing wheezing and urgency, this is caused by excess Yin-cold. It is appropriate to administer Xiao Qinglong Tang (Xiao Qinglong Decoction).
Ingredients: Guixin (Cinnamomi Ramulus, 1 liang), Wuweizi (Schisandrae Fructus, 0.5 liang), Mahuang (Ephedrae Herba, 1 liang, remove root and joints), Baishaoyao (Paeoniae Radix Alba, 2 liang), Xixin (Asari Radix et Rhizoma, 3 fen), Ganjiang (Zingiberis Rhizoma, 3 fen).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, even after sweating therapy, if there is discomfort in the chest and heart, frequent headaches, disharmony of Stomach Qi, and poor appetite for congee, it is appropriate to administer Qianhu San (Qianhu Powder).
Ingredients: Qianhu (Peucedani Radix, 0.5 liang, remove rhizome), Banxia (Pinelliae Rhizoma, 1 fen, washed seven times in hot water to remove slipperiness), Gancao (Glycyrrhizae Radix et Rhizoma, 0.5 liang, honey-fried until slightly red, cut into pieces), Guixin (Cinnamomi Ramulus, 0.5 liang), Renshen (Ginseng Radix, 0.5 liang), Danggui (Angelicae Sinensis Radix, 0.5 liang, cut into pieces, lightly stir-fried), Gegen (Puerariae Lobatae Radix, 0.5 liang, cut into pieces), Chaihu (Bupleuri Radix, 0.5 liang, remove seedlings), Chenjupi (Citri Reticulatae Pericarpium, 0.5 liang, soaked in hot water, remove white pith, baked), Muxiang (Aucklandiae Radix, 0.5 liang), Xuanfuhua (Inulae Flos, 0.5 liang).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water, half a banfen of Shengjiang (Zingiberis Rhizoma Recens), and three dates. Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, with abdominal and hypochondriac fullness, chest discomfort, limb pain, cough, aversion to cold, wheezing, and high fever, it is appropriate to administer Baizhu San (Baizhu Powder).
Ingredients: Baizhu (Atractylodis Macrocephalae Rhizoma, 3 fen), Qianhu (Peucedani Radix, 3 fen, remove rhizome), Gegen (Puerariae Lobatae Radix, 3 fen, cut into pieces), Sangbaipi (Mori Cortex, 3 fen, cut into pieces), Chuan Shengma ( Cimicifugae Rhizoma, 0.5 liang), ChiShaoyao (Paeoniae Radix Rubra, 1 liang), Shigao (Gypsum Fibrosum, 1.5 liang), Jingjie (Schizonepetae Spica, 0.5 liang), Zihuang (Scutellariae Radix, 3 fen).
The above ingredients are crushed, sifted, and made into a powder. Take 5 qian per dose. Add one large zhan of water, half a banfen of Shengjiang (Zingiberis Rhizoma Recens), and fifty grains of Chidou (Sojae Semen Praeparatum). Decoct until reduced to five parts. Strain and take warm at any time.

For treating cold damage on the fourth day, with unresolved irritant heat and sluggishness of the Large and Small Intestines, it is appropriate to administer Puxiao San (Puxiao Powder).
Ingredients: Chuan Puxiao (Natrii Sulfas, 3 fen), Xijiaoxie (Rhino Ceris Cornu, 3 fen), Zhizi Ren (Gardeniae Semen, 0.5 liang), ChiShaoyao (Paeoniae Radix Rubra, 3 fen), Huangqin (Scutellariae Radix, 3 fen), Chenjupi (Citri Reticulatae Pericarpium, 3 fen, soaked in hot water, remove white pith, baked), Chuan Dahuang (Rhei Radix et Rhizoma, 3 fen, cut into pieces, lightly stir-fried), Chaihu (Bupleuri Radix, 1 liang, remove seedlings).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water, thirty slices of Danzhuye (Lophatheri Herba), and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to six parts. Strain and take warm frequently at any time. The degree of bowel movement is the limit.

For treating cold damage on the fourth day, with heavy head, stiff body, and pain in the waist and spine, it is appropriate to administer Gegen San (Gegen Powder).
Ingredients: Gegen (Puerariae Lobatae Radix, 1 liang, cut into pieces), Gancao (Glycyrrhizae Radix et Rhizoma, 1 liang, honey-fried until slightly red, cut into pieces), Guixin (Cinnamomi Ramulus, 1 liang), Daqing (Isatidis Folium, 3 fen), Huangqin (Scutellariae Radix, 0.5 liang), Shigao (Gypsum Fibrosum, 1 liang), ChiShaoyao (Paeoniae Radix Rubra, 3 fen), Mahuang (Ephedrae Herba, 2 liang, remove root and joints).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water, half a banfen of Shengjiang (Zingiberis Rhizoma Recens), and three dates. Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, with unresolved irritant heat and constipation of the Large and Small Intestines, it is appropriate to administer Xijiao San (Xijiao Powder).
Ingredients: Xijiaoxie (Rhino Ceris Cornu, 3 fen), Huangqin (Scutellariae Radix, 1 liang), Chaihu (Bupleuri Radix, 1 liang, remove seedlings), Zhizi Ren (Gardeniae Semen, 0.5 liang), Digupi (Lycii Cortex, 3 fen), Chuan Dahuang (Rhei Radix et Rhizoma, 1.5 liang, cut into pieces, lightly stir-fried), Chuan Puxiao (Natrii Sulfas, 1 liang), Mutong (Akebiae Caulis, 2 fen, cut into pieces).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one large zhan of water. Decoct until reduced to five parts. Strain and take warm at any time. The degree of mild diarrhea is the limit.

For treating cold damage on the fourth day, with headache, stiffness and oppression in the back and shoulders, painful joints, dry mouth, and irritability, it is appropriate to administer Yichen San (Yichen Powder).
Ingredients: Yichen (Artemisiae Scopariae Herba, 1 liang), Chaihu (Bupleuri Radix, 1 liang, remove seedlings), Gancao (Glycyrrhizae Radix et Rhizoma, 0.5 liang, honey-fried until slightly red, cut into pieces), ChiShaoyao (Paeoniae Radix Rubra, 2 fen), Fangfeng (Saposhnikoviae Radix, 2 fen, remove rhizome), Fuzi (Aconiti Lateralis Radix Praeparata, 1 liang, processed until cracked, remove skin and navel).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water and half a banfen of Shengjiang (Zingiberis Rhizoma Recens). Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, without prior emesis, it is appropriate to administer Xiexin Tang (Xiexin Decoction).
Ingredients: Chuan Dahuang (Rhei Radix et Rhizoma, 2 liang, cut into pieces, lightly stir-fried), Huanglian (Coptidis Rhizoma, 1 liang, remove roots), Huangqin (Scutellariae Radix, 1 liang), Fuzi (Aconiti Lateralis Radix Praeparata, 1 liang, processed until cracked, remove skin and navel).
The above ingredients are coarsely pounded and sieved into a powder. Take 3 qian per dose. Add one zhong zhan of water. Decoct until reduced to six parts. Strain and take warm at any time.

For treating cold damage on the fourth day, where the three Yin meridians are affected, with a floating and slippery pulse, abdominal fullness, hot mouth, dry tongue with thirst, and difficult defecation, it is appropriate to administer Sanhuang San (Sanhuang Powder).
Ingredients: Huangqin (Scutellariae Radix, 1 liang), Zhizi Ren (Gardeniae Semen, 1 liang), Chuan Dahuang (Rhei Radix et Rhizoma, 1.5 liang, cut into pieces, lightly stir-fried).
The above ingredients are crushed, sifted, and made into a powder. Take 4 qian per dose. Add one zhong zhan of water, twenty-seven leaves of Zhuye (Bambusae Folium), and 2 qian of Puxiao Mo (Natrii Sulfatis Pulvis). Decoct until reduced to six parts. Strain and take warm before meals. Stop the medicine when bowel movements become smooth; if not, take again.

For treating cold damage on the fourth day, where toxic heat enters the Stomach causing throat obstruction and oppression, it is appropriate to administer Tutan San (Tutan Powder).
Ingredients: Goudi (Cucumeris Fructus, 1 fen), Dingxiang (Caryophylli Flos, 1 fen), Chixiaodou (Phaseoli Semen, 0.5 fen, roasted).
The above ingredients are finely pounded and sieved into a powder. Take 2 qian per dose, mixed with warm water. Take on an empty stomach to induce vomiting. Afterwards, consume Congchi Zhou (Green Onion and Fermented Soybean Porridge) to nourish the body.

For treating cold damage with incessant sweating for three or four days, nausea in the chest, and a desire to vomit, it is appropriate to use an emetic formula.
Ingredients: Chidou (Sojae Semen Praeparatum, 2 he), Yan (Sal, 0.5 liang), Mi (Mel, 1 he).
The above ingredients are decocted in one large zhan of water until reduced to seven parts. Strain and take all at once on an empty stomach. Vomiting should occur after some time. If walking for ten li does not induce vomiting, take again.

Another prescription.
Ingredients: Kushen (Sophorae Flavescentis Radix, 0.5 liang, cut into pieces), Gancao (Glycyrrhizae Radix et Rhizoma, 1 fen, raw, cut into pieces), Chixiaodou (Phaseoli Semen, 27 seeds, roasted).
The above ingredients are decocted in one large zhan of water until half a zhan remains. Strain and take all at once on an empty stomach. Vomiting should occur. If the condition does not improve, induce vomiting again, primarily using Kushen (Sophorae Flavescentis Radix).

For treating cold damage on the fourth day, with persistent chills and fever, headache, and painful joints throughout the body, indicating toxic heat in the chest, it is appropriate to administer Songluo San (Songluo Powder).
Ingredients: Songluo (Usnea, 0.5 liang), Chuan Shengma (Cimicifugae Rhizoma, 1 liang), Gancao (Glycyrrhizae Radix et Rhizoma, 1 liang, raw), Hengshan (Dichroae Radix, 0.5 liang).
The above ingredients are crushed, sifted, and made into a powder. Take 5 qian per dose. Add one large zhan of water. Decoct until reduced to seven parts. Add 2 qian of Cumi (Coarse Rice) or Chamomile Tea Powder. Boil for one more boil. Strain and take warm on an empty stomach. If not vomited, take again after the time it takes to walk three or four li. The degree of vomiting is the limit.

For treating cold damage on the fourth day, after already having vomited, it is appropriate to use another emetic method.
Ingredients: Kushen Mo (Sophorae Flavescentis Radix Pulvis, 2 qian).
Mix the above with 5 he of warm wine and take. Recovery occurs upon vomiting.

For treating cold damage on the fourth day, with fullness and oppression in the chest and heart, use an emetic method.
Ingredients: Zhudan (Sus Scrofa Bile, one gallbladder, extract juice).
Mix the above with one small zhan of Vinegar and one small zhan of Wine. Warm the mixture and divide into two doses. Vomiting should occur, leading to recovery.