After chemotherapy for lung cancer, watermelon can be consumed moderately, but it should not be consumed excessively, which should be analyzed by patients themselves. Lung cancer is a malignant tumor of respiratory system caused by heredity, smoking and other factors, and the main treatment method after the occurrence of the disease is chemotherapy, which uses blood to make chemotherapeutic drugs reach the lesions and achieve the purpose of killing tumor cells. The development of the tumor and the side effects of chemotherapy can cause certain consumption to the patients. Watermelon is a common fruit, which contains a variety of nutrients, such as sugar; vitamins such as vitamin A, B1, B2; calcium, phosphorus, potassium and other trace elements. It can provide patients with certain energy and nutrients, and can improve their immunity. However, moderate consumption is enough to avoid causing gastrointestinal discomfort. It is recommended that patients maintain a good state of mind during chemotherapy, pay attention to rest, and actively consult a doctor if they feel unwell.