r-chop regimen refers to the chemotherapy regimen of rituximab + cyclophosphamide + doxorubicin + vincristine + prednisone, which is the first-line chemotherapy regimen for diffuse large B-cell tumors, and attention should be paid to the detection of the function of important organs and the toxicity and side-effects of chemotherapy before, during, and after the chemotherapy, and the corresponding treatment should be given. 1. Before chemotherapy: liver and kidney function, cardiac enzymes, blood routine and other tests should be perfected to exclude the contraindications to chemotherapy, and chemotherapy should be suspended for those who have serious liver and kidney function damage, low leukocytes in blood routine, or whose blood picture suggests infection. 2. During chemotherapy: after eliminating the contraindications to chemotherapy and starting chemotherapy, attention should be paid to the monitoring of toxic and side effects of chemotherapy during the chemotherapy period. For the occurrence of nausea, vomiting and other reactions, antiemetic and other symptomatic treatments need to be given, such as commonly used ondansetron and other medications, and at the same time should be given to hepatoprotective medications such as glucuronide and other treatments, and be given to sufficient hydration to promote the excretion of drugs and to protect the renal function, and other measures. 3. After chemotherapy: patients should be rechecked for liver and kidney function, cardiac enzymes, blood routine and other indexes after chemotherapy to monitor whether there is any damage to important organs, and be treated actively. For those who have bone marrow suppression after chemotherapy, recombinant human granulocyte factor can be given to stimulate myelopoietic therapy. The r-chop regimen should exclude contraindications to chemotherapy and be carried out under the guidance of physicians experienced in antitumor therapy.