Enlarged lymph nodes are lymph nodes that have proliferated beyond its original size. Lymph nodes are not only the site of immunity, proliferation and filtration of the body, but also the location of receiving antigenic stimulation to produce immune response, which can promptly localize the health condition of the body. The causes of swollen lymph nodes are generally divided into the following categories: a. When the body is infected by viruses or bacteria, acute and chronic inflammation will be induced, causing swollen lymph nodes, but the swelling usually recovers or disappears on its own as the inflammation and primary disease improve; b. Certain primary tumors, such as lymphoma, various types of acute and chronic leukemia, plasma cell tumors, or lung cancer, liver cancer, breast cancer, nasopharyngeal cancer and other malignant tumors metastasized and triggered Lymph node enlargement, such as metastasis of nasopharyngeal cancer to cervical lymph nodes and metastasis of gastric cancer to left supraclavicular lymph nodes; third, lymph node enlargement caused by biological factors, chemical factors and metabolic stimuli, and lymph node enlargement caused by reactive proliferation of lymphocytes mononuclear macrophages in lymph nodes; fourth, lymph node enlargement caused by lymphatic structures or lymph nodes with a large number of tissue cells proliferation. There is no need to panic when lymph node enlargement occurs, as most of them are inflammatory reactive proliferative lymph node enlargement. However, it should not be ignored, and once a persistently abnormally enlarged lymph node with other abnormal symptoms is found, prompt medical attention should be sought for early intervention to avoid delay.