In clinical work, some lung cancer patients will mention that they have been in a bad mood for the past few months, quarreled with relatives or were cheated in business, etc. Some even say that their disease is caused by their anger. Is there any theoretical basis for this statement? Let us talk about this issue today. Low mood or poor mood will affect the immunity of the body, resulting in lower immunity and lower defense mechanism of the body, which will weaken the immune system and reduce the clearance rate of malignant tumor system in the body. Enhanced hostility or frequent negative emotions can also cause immune system disorders, which can lead to the development of tumors, as has been agreed in modern immunology. One study confirmed that chronic negative emotions can increase the risk rate of lung cancer more than twofold compared to normal people. Studies have concluded that poor self-regulation, unhappy marital life, poor interpersonal relationships or difficulty adapting to the environment can increase the risk of lung cancer more than tenfold, and there is a correlation with smoking. Smokers coupled with poor emotional well-being are more likely to develop lung cancer. The specific mechanism of the study is not completely clear, but from this study, maintaining an optimistic and cheerful attitude in general can reduce the occurrence of lung cancer. Therefore, there is a relationship between mood and the occurrence of lung cancer.