If the lung cancer is advanced and cannot eat, it will adversely affect the survival of the patient. If the patient is receiving fluids, the survival period may be about 1-3 months. If there is no infusion, the patient’s survival period is about 1 week, which is prone to systemic cachexia and failure and life-threatening. Patients with advanced lung cancer cannot eat, which indicates that the systemic function is relatively low, there is cachexia state, hypoproteinemia, and they are prone to serious heart and lung infections as well as respiratory failure. Cough, sputum, blood in sputum, and even fever with pleural effusion appear. The above conditions tend to aggravate the patient’s symptoms of systemic failure and make treatment extremely difficult. Active nutritional therapy as well as anti-infection therapy is needed to prolong the patient’s life and improve the quality of survival. If the patient cannot be given fluids and the life passage is terminated, the survival period will be even shorter, and the complications will easily occur in about 1 week and endanger the life. In conclusion, patients with advanced lung cancer have poor food intake, which indicates that the spleen and stomach function are severely reduced and easily endanger their lives in a short period of time, and need to be given nutritional support therapy as early as possible.