治太阳病项背KT KT ，。无汗恶风者。又治太阳与阳明合病。必自下利。此方主之。
葛根（四两） 麻黄（三两 去节。） 甘草（二两 炙。） 芍药（二两） 桂枝（二
两）
上七味。 咀。以水一斗。先煮葛根、麻黄。减二升。去上沫。纳诸药。煮取三升。去
滓。温服一升。覆取微似汗。不须啜粥。余如桂枝法将息及禁忌。
歌曰 四两葛根三两麻。枣枚十二效堪嘉。桂甘芍二姜三两。无汗憎风（项背KT
KT太阳病。）下利（太阳阳明合病）夸。
蔚按。第二方桂枝加葛根汤与此汤。俱治太阳经输之病。太阳之经输在背。经云。邪入
于输。腰脊乃强。师于二方皆云。治项背KT KT 。KT KT 者。小鸟羽短。欲飞不能
飞。而伸颈之象也。但前方治汗出。是邪从肌腠而入输。故主桂枝。此方治无汗。是邪从肤
表而入输。故主麻黄。然邪既入输。肌腠亦病。方中取桂枝汤全方加葛根、麻黄。亦肌表两
解之治。与桂枝二麻黄一汤同意。而用却不同。微乎微乎。葛根性用解见第二方。
张令韶曰。太阳与阳明合病。必自下利者。太阳主开。阳明主阖。今太阳合于阳明。不
从太
上腾。气腾于上。利自止矣。
治太阳与阳明合病。不下利。但呕者。此方主之。
葛根汤原方。加半夏（半升 洗。） 煎服同前。
歌曰 二阳（太阳与阳明合病。）下利葛根夸。不利旋看呕逆嗟。须取原方照分两。半
升半夏
张令韶曰。不下利但呕者。太阳之气仍欲上达而从开也。因其势而开之。故加半夏以宣
通逆
Treats Taiyang disease (disease of the Taiyang channel) characterized by stiffness and discomfort in the neck and back, absence of sweating, and aversion to wind. It also treats concurrent diseases of the Taiyang and Yangming channels, where spontaneous diarrhea is inevitable; this formula is the primary treatment.
Puerariae Radix (Ge Gen, 葛根) (4 liang)
Ephedrae Herba (Mahuang, 麻黄) (3 liang, remove joints)
Glycyrrhizae Radix et Rhizoma (Gan Cao, 甘草) (2 liang, honey-fried)
Paeoniae Radix Alba (Baishao, 芍药) (2 liang)
Cinnamomi Ramulus (Guizhi, 桂枝) (2 liang)
Take the above seven ingredients, coarsely crush them. Add ten dou of water, first decoct Puerariae Radix and Ephedrae Herba until the volume reduces by two dou, skim off the foam on the surface, then add the remaining herbs. Decoct until three sheng of liquid remains, strain to remove dregs. Take one sheng warm. Cover with blankets to induce a slight sweat. There is no need to drink hot porridge to assist sweating. Other dietary regimens and contraindications should follow the instructions for Guizhi Tang (Cinnamon Twig Decoction).
Song verse:
Four liang of Ge Gen, three liang of Mahuang,
Twelve dates bring excellent efficacy.
Two liang each of Guizhi and Gancao, three liang of Shengjiang,
Praised for treating anhidrosis and aversion to wind (Taiyang disease with neck/back stiffness) and diarrhea (concurrent Taiyang-Yangming disease).
Commentary by Wei: The second formula, Guizhi Jia Ge Gen Tang (Cinnamon Twig Decoction plus Pueraria Root), and this formula (Gegen Tang), both treat disorders of the Taiyang channel's transmission points. The transmission points of the Taiyang channel are located on the back. As stated in the medical classics: "When pathogenic factors enter the transmission points, the lower back and spine become stiff." In the clauses for both formulas, Zhang Zhongjing mentions treating "stiffness and discomfort in the neck and back." The term "KT KT" (representing stiffness/tightness) resembles a small bird with short feathers that wishes to fly but cannot, thus stretching its neck. However, the former formula (Guizhi Jia Ge Gen Tang) treats cases with sweating, indicating that pathogens entered the transmission points via the muscle interstices (Ji Cou); hence, it uses Guizhi Tang as the base. This formula (Gegen Tang) treats cases without sweating, indicating that pathogens entered the transmission points from the skin and surface; hence, it uses Mahuang as the primary agent. Since the pathogens have entered the transmission points, the muscle interstices are also affected. The formula takes the complete Guizhi Tang and adds Puerariae Radix and Ephedrae Herba, representing a treatment that resolves both the exterior and the interior/transmission points simultaneously. This aligns with the principle of Guizhi Er Mahuang Yi Tang (Double Cinnamon Twig Decoction and Single Ephedra Decoction), though the dosage ratios differ. The subtlety is profound. The properties and actions of Puerariae Radix were explained in the commentary for the second formula.
Zhanglingshao states: In concurrent diseases of Taiyang and Yangming, spontaneous diarrhea occurs because Taiyang governs opening (release) and Yangming governs closing (closure). When Taiyang merges with Yangming, if the Qi does not ascend upward, diarrhea ensues. If the Qi ascends properly, the diarrhea will cease.
For concurrent diseases of Taiyang and Yangming where there is no diarrhea but only vomiting, this formula is the primary treatment.
Use the original Gegen Tang formula, add Banxia (Pinelliae Rhizoma, 半夏) (half sheng, washed). Decoct and administer as before.
Song verse:
Concurrent Taiyang-Yangming disease with diarrhea praises Gegen Tang;
If no diarrhea but vomiting and reflux occur, observe carefully.
Take the original formula according to proportions,
Add half a sheng of Banxia.
Zhanglingshao states: When there is no diarrhea but only vomiting, it indicates that Taiyang Qi still desires to ascend and follow the trend of "opening." To follow this trend and promote unblocking, Banxia is added to disperse and unblock the rebellious Qi.