In the nearly 2,000 years of history of the Chinese people, the Yellow Emperor’s Classic of Internal Medicine has been the source of the formation of Chinese medical theory, and the essence of its ideas has been the guiding principle for the practice of medicine and the criterion for the theory of later generations of doctors. The importance of yang energy and the harmony of yin and yang has been a part of the theory of Nei Jing throughout. The “Sheng Qi Tong Tian Lun” cloud: “Yang Qi is like the sky and the sun, the loss of its place will be broken life and not manifest, so the sky should be bright with the sun.” The ancients compared the important role of Yang Qi in the human body to the relationship between the sky and the sun, if there is no sun in the sky, then the earth will be dark and cold, and everything cannot grow. Therefore, the sun must shine for heaven and earth to function. If the human body loses Yang Qi, life will cease to exist. “Yang is the source of the body’s vital activity. Yang Qi is the source of life activity of the human body, and is the dominant force in the life activity of all things. The biochemistry, transmission and excretion of the body’s essence and fluids, as well as the transmission and excretion of metabolites, all depend on the role of Yang Qi to achieve biochemical endlessness. The body’s ability to warm, water and grain can be transformed, rising to nourish the spirit, reaching down to soften the tendons, is also inseparable from Yang Qi. It can be seen that Yang Qi is not only the body’s functional activity itself, but also the substance to maintain these functional activities, which can promote or maintain the growth and development of the body, the functional activities of the internal organs and has the role of warming, fixing, promoting and transforming, etc. The importance of Yang Qi can be seen. Tumors are called “accumulation” and “obstruction” in ancient times, and there are many similar descriptions in the Yellow Emperor’s Classic of Internal Medicine. There are many similar descriptions in the Yellow Emperor’s Classic of Internal Medicine, such as “The Beginning of All Diseases”, which says, “The beginning of accumulation is born from cold, and the syncope becomes accumulation. The “Spiritual Pivot? Five Changes” says: “Between the intestines and stomach, cold and temperature do not follow each other, and the evil gas arrives slightly, and the accumulation stays there, and the cold is astringent, and the gas is astringent, then the accumulation is born.” Ling Shu? Water distension: “intestinal Qin what? said: cold outside the intestine, gangrene meat is born. Its first birth is as big as a chicken egg.” This shows that the causes of accumulation in the Nei Jing are not only Yang deficiency and cold accumulation. Without yang, the heart cannot transport blood; without yang, the spleen cannot transform water and grain; without yang, the liver cannot drain water; without yang, the lungs cannot promote and descend; and without yang, the kidneys can be closed with cloudy yin. Insufficient yang energy, a slight obstruction, a hundred diseases reborn. Due to the deficiency of Yang Qi in the human body, the heat is insufficient, the warmth is not promoted, the fluid and essence run slowly, so that cold arises from it, resulting in stagnation of Qi and blood stasis, dampness and phlegm condensation, which leads to the internal condensation of cold and phlegm, and the accumulation of tangible obstruction is formed. The deficiency of yang energy can also lead to the body’s lack of external defense, and the external evil of the six leprechauns can take advantage of the deficiency to enter the body, resulting in the imbalance of qi, blood, yin and yang in the internal organs of the body, resulting in pathological changes such as qi stagnation, blood stasis, phlegm and dampness accumulation, which can develop into tumors over time. The Treatise on the Origin of Diseases says: “The accumulation is caused by the disharmony of yin and yang, the weakness of the internal organs, the wind and evil, and the fight with the qi of the internal organs. Modern medical biology believes that tumor cells are a group of immature cells. The lower the degree of differentiation, the higher the degree of malignancy. The lower the degree of differentiation, the higher the malignancy. In Chinese medicine, Yang Qi is the driving force to promote the growth and development of the body. The so-called “Yang Qi” corresponds to the cell differentiation and apoptosis related to cellular executive functions. If Yang Qi is deficient, the growth and development of the body will be delayed, and the cells will show immature differentiation. The more Yang Qi deficiency, the lower the differentiation of cells, the more abnormal development and uncontrolled proliferation, and the higher the degree of malignancy. Modern immunology believes that thousands of cells in the body mutate every day, which can be cleared by the body’s immune system under normal circumstances, but tumor cells in cancer patients can escape from immune surveillance and keep proliferating, which is related to the dysregulation of Yang’s solid protection. Yang is also known as “Wei Yang” and “Wei Qi”, which are like the body’s guards, distributed among the skin couples to defend against external evil. As long as the Yang energy is strong, it can prevent all diseases from invading. Tumor cells are evil to the human body, and the human body is deficient in yang energy, so it is unable to resist the evil, and tumor cells will keep growing, as the saying goes, “Where evil comes together, its qi will be deficient”. Therefore, for the treatment of tumor, if we only adopt heat-clearing and detoxifying herbs, and only work on cold and cooling herbs such as white flowering snake tongue herb, half-root lotus and flea-hew, it will definitely be contrary to the principle of treatment. The essence of Chinese medicine in treating tumors is to help the righteous to dispel the evil, to dispel the evil without harming the righteous, to maintain a good quality of life, or even to coexist with the tumor.