Precautions after stage III chemotherapy for diffuse large B-cell lymphoma mainly include regular checking of blood routine and liver and kidney functions, paying attention to hygiene to avoid infection, paying attention to diet and keeping warm, etc. Diffuse large B-cell lymphoma belongs to malignant tumors, which may be life-threatening if not treated in time. However, the prognosis of this type of lymphoma is relatively good, and it is possible to achieve clinical cure through standardized radiotherapy and chemotherapy. After stage III chemotherapy for diffuse large B-cell lymphoma, regular review of blood routine and liver and kidney function is needed, chemotherapy drugs have certain effects on liver and kidney, timely review can try to avoid irreversible consequences caused by excessive damage to liver and kidney. In addition, bone marrow suppression often occurs after chemotherapy, manifested as a decrease in white blood cells, platelets, etc., and patients are more likely to be infected, and once infected, it may affect the next chemotherapy, so they should try to avoid going to public places, and avoid eating unclean food. After chemotherapy, patients have weaker physique and poorer gastrointestinal function, so they should pay attention to light diet, easy to digest, and avoid eating cold and stimulating food. After stage III chemotherapy for diffuse large B-cell lymphoma, patients should follow up regularly, and if any discomfort occurs, consult the doctor in time for active treatment.