Negative lymph nodes prove that the pathological examination of lymph nodes is normal, no lymph nodes or lymphadenitis, or tumor metastasis, lymphoma, connective tissue disease, that is, there is no positive. Lymph nodes as an important component of our body’s immune system organs, its most important role is to filter the lymphatic fluid, and then remove the invasion of lymphatic fluid 99% of the bacteria, is our body’s resistance to foreign viruses, bacteria invasion of the natural barriers to the protection of the lymph nodes, our body can effectively reduce the probability of contamination with infectious diseases. Malignant tumors can appear lymphatic metastasis, and lymph nodes can also appear primary tumor lesions, that is, lymphoma. In this case, pathological examination of lymph nodes can reveal infiltration of tumor cells. Pathological examination of lymph nodes in connective tissue disease reveals infiltration of lymphocytes and plasma cells in the tissues.