In this article, left-sided cervical lymph node refers to a lymph node found enlarged in that area. The lymph nodes in this area are not normally enlarged and cannot be felt by palpation. It is possible to find enlargement in the case of infections, tuberculosis of the lymph nodes, and metastatic tumors. Disease factors can also lead to the appearance of lymph nodes on the left side of the neck, including the following main causes: 1. Infection: Bacterial and viral infections in the neck, mouth and throat can easily cause enlargement of the lymph nodes, resulting in localized pain and pressure, which can subside after anti-inflammatory treatment. 2. Tuberculosis of lymph nodes: If the lymph nodes are infected with Mycobacterium tuberculosis, lymphatic tuberculosis may appear, which is manifested as enlarged lymph nodes, and may even be accompanied by abscesses. Combined application of isoniazid, rifampicin, ethambutol and other drugs is needed, and surgery is needed to remove the abscess if necessary. 3. Malignant tumors: the neck is a good place for malignant tumors, such as lung cancer, thyroid cancer, breast cancer, laryngeal cancer, nasopharyngeal cancer and so on. They are usually round, large in size, small in activity, unclear in boundary, and most of them have the history of primary tumor. And lymphoma, leukemia can also lead to enlarged lymph nodes in the area. After finding enlarged lymph nodes in the left neck, it is necessary to consult a doctor in time, and after diagnosis, it is necessary to carry out standardized treatment under the guidance of clinicians.