Lung cancer is caused by the deficiency of positive qi, the imbalance of yin and yang, and the entry of evil toxins into the lung by taking advantage of the deficiency. Therefore, lung cancer is a disease caused by deficiency, and the deficiency causes actuality, which is a disease of general deficiency and local actuality. The deficiency of lung cancer is mostly Yin deficiency, Qi and Yin deficiency, while the actuality is no more than the pathological changes of Qi stagnation, blood stasis, phlegm coagulation, and toxin accumulation. The disease is located in the lung, but it is closely related to the liver, spleen and kidney because the liver is responsible for draining, the spleen is responsible for transporting and transforming water and dampness, and the kidney is responsible for evaporation of water.