Shegan Mahuang Decoction comes from "Golden Chamber Synopsis·Lung Absence, Lung Carbuncle Cough, Upper Qi Disease and Pulse Syndrome Seventh". often use it to treat lung cancer with phlegm-heat stickiness and unfavorable Qi machine. The prominent manifestations of lung cancer are coughing, shortness of breath, phlegm in the throat, and even continuous coughing and wheezing, hard to come out of sputum, tears and sobbing, chest pain, blood in the sputum, red tongue, thin white coating, and pulse count.

      Shegan Mahuang Decoction has the functions of resolving phlegm and throat, clearing lungs and lowering qi. It is the same as Xiaoqinglong Decoction and it belongs to Jiebiaohuayin prescription, but the symptoms of wind-cold symptoms are milder in the front, and the syndrome is phlegm-drinking stagnation and lung-qi upset. Therefore, on the basis of Xiaoqinglong Decoction, cassia twig, peony, licorice are subtracted, and medicines such as shegan, coltsfoot, and aster for relieving cough and asthma are added. It can be seen that Xiaoqinglong Decoction is the main treatment for the superficial, the power of relieving the superficial and cold is great, and the Shegan Mahuang Decoction is the main treatment for the inside, and the power of lowering the breath and relieving asthma is strong.

      Zhang Zhongjing said: "Coughing and breathing, the sound of water in the throat, the master of Shegan Mahuang Decoction." Although a few short words, he grasped the characteristics. It is a prescription that is quite common in lung cancer clinically and has rapid effect.