The causes of mesenteric lymphadenitis are mainly seen in infections, intestinal abnormalities, and lymph node metastases, as follows: 1. Infections: Lymphadenitis most likely caused by bacteria, but may also be caused by viruses, and requires a visit to the hospital to improve relevant tests, such as blood tests, C-reactive protein, and ultrasound. If bacterial infection is considered, antibiotics should be given for treatment. If it is considered to be caused by viral infection, it needs to be treated with antiviral drugs, and at the same time, it can be treated with traditional Chinese medicine. 2. Intestinal abnormalities: it may be caused by abnormal intestinal diseases, such as acute appendicitis, intussusception, intestinal torsion, etc. It is necessary to go to the hospital to check the abdominal CT and laboratory tests to clarify, and according to the results, it may be necessary to perform surgery. 3. Lymph node metastasis: it may be caused by lymph node metastasis of malignant tumor, which requires further improvement of tumor markers and colonoscopy for clarification.