Reactive lymph nodes are lymph nodes that belong to the immune organs of the body. When inflammation occurs in the body locally or systemically, it will stimulate reactive enlargement of lymph nodes, which is distinguished from metastatic enlargement of lymph nodes caused by cancer and so on. The typical manifestation is reactive lymph node enlargement, in which the longitudinal to transverse diameter ratio of the lymph nodes is greater than one and the corticomedullary boundary is clear, while in the case of metastatic lymph node enlargement caused by cancer, the corticomedullary boundary is unclear and the longitudinal to transverse diameter ratio is generally less than one. Reactive lymph nodes belong to the immune response of the body and are mostly caused by lymph node enlargement due to stimulation in the case of inflammation. If there are no special symptoms such as pain, no special treatment is usually needed, and the swollen lymph nodes will slowly subside when the inflammation of the primary lesion subsides. In addition, during the period of reactive lymph node enlargement, it is necessary to pay attention to a light diet, eat less spicy and stimulating food, drink more water, pay attention to rest, etc. to strengthen the body’s resistance.