Multiple lymph nodes in retroperitoneum and mesenteric root may be caused by lymph node metastasis such as peritoneal lymphadenitis and abdominal malignant tumors, which can be treated by drugs and surgery. 1. Peritoneal lymphadenitis is caused by inflammation due to unclean diet, bacterial infection, viral infection and so on. There will be abdominal pain, diarrhea, body fever and other symptoms, which can be treated with oral levofloxacin, metronidazole and other drugs under the guidance of the doctor. 2. Abdominal malignant tumors caused by lymph node metastasis, malignant tumors of lymphoid follicles on the stomach wall can be metastasized through the lymphatic system, and symptoms such as lethargy and fever will appear, which can be treated with drugs such as cefazolin and ibuprofen as prescribed by doctors, and it is also recommended to take the method of surgical resection of lymphoma foci for treatment. Patients with multiple lymph nodes in retroperitoneum and mesenteric root should go to the hospital as soon as possible to clarify the cause of the disease, and carry out standardized treatment under the guidance of doctors.