Currently there are several options for chemotherapy regimens for gastric and colorectal cancers internationally, mainly postoperative adjuvant chemotherapy regimens, which are constantly updated with the progress of basic drug research and clinical study results. At present, the most commonly used first-line chemotherapy regimen for gastric and colorectal cancers, XELOX regimen, is increasingly used in clinical practice, which not only has evidence of therapeutic effects, but also has better patient acceptability and relatively less side effects. What is the XELOX (CAPEOX) regimen? It is the abbreviation for the specific chemotherapy regimen, which is a 3-week regimen, that is, every 21 days is a chemotherapy cycle, and the general postoperative adjuvant chemotherapy duration is six months, which is 8 cycles. The specific regimen is: oxaliplatin, 130 mg/m2 (body surface area) on the first day, and oral capecitabine, 1000 mg/m2 (body surface area) twice a day (once in the morning and once in the evening after meals) on days 1-14, followed by a week of rest, which is a complete chemotherapy cycle. What is the situation to apply this chemotherapy regimen? Generally, preoperative neoadjuvant therapy or postoperative adjuvant chemotherapy for gastric cancer, or even palliative chemotherapy for advanced gastric cancer, which are the first-line chemotherapy regimens, but of course there are other regimens, depending on the advice of the treating physician. Similarly, postoperative adjuvant chemotherapy for colorectal cancer and basic chemotherapy for advanced colorectal cancer are also first-line chemotherapy regimens, but again, they are not the only chemotherapy regimens, and there are other regimens, which need to refer to the advice of the treating physician. The indications for chemotherapy are mainly based on the patient’s disease stage and physical condition. Early stage gastrointestinal cancer definitely does not require chemotherapy, while patients with intermediate and advanced stages need to be treated according to their specific conditions, and the choice of chemotherapy regimen should be decided by a specialist according to their specific conditions. What are the advantages of this chemotherapy regimen compared with other first-line chemotherapy regimens? For post-operative adjuvant chemotherapy for gastric cancer, this regimen is currently recommended as first-line chemotherapy by NCCN guidelines and is supported by large multicenter clinical studies. Similarly, for colorectal cancer, it is also one of the first-line chemotherapy regimens recommended by the guidelines. There is no significant difference in treatment efficacy between this regimen and complete intravenous chemotherapy regimens such as FOLFOX or FOLFIRI, but the number of cycles of chemotherapy for patients is reduced from 12 to 8, and there is no need for continuous pumping of chemotherapy drugs (the other two regimens require continuous pumping of chemotherapy drugs for 46-18 hours), and the regimen can be administered through peripheral intravenous infusion of oxaliplatin, which usually ends in 2 hours, unlike other regimens that require 48 hours. This allows chemotherapy to be administered through a peripheral vein, which eliminates the need for a central venous catheter to be left in place for long periods of time. This is very convenient for the patient, at least because it eliminates the need for regular hospital visits to flush the central venous catheter (which would otherwise be prone to thrombosis and block the infusion line) and reduces or even avoids thrombosis (which is a high risk factor due to the fact that the central venous catheter is inside the vessel). What do I need to pay attention to when applying this regimen of chemotherapy? 1, the first time chemotherapy, you need to be alert to the problem of chemotherapy drug allergy. It is similar to penicillin allergy, patients may experience chest tightness, shortness of breath, or skin rash, or severe cardiac arrest when applying chemotherapy drugs, but the probability of this happening is very low. Therefore, in the first chemotherapy, start infusion slowly, closely observe the patient’s condition, if there is any discomfort, promptly find the doctor and nurse, immediately stop chemotherapy, symptomatic treatment. 2, oral capecitabine, do not arbitrarily stop or change the dose or frequency of dosing. The program is a combination of intravenous oral chemotherapy, a few patients may not listen to or remember the doctor’s advice, that only infusion is chemotherapy, oral chemotherapy drugs are not taken on time or on the oral. Generally do not stop the dose and frequency at will, it will affect the effect of treatment. Unless the side effects are large, the doctor will adjust the dose according to the specific situation. 3, regular review of blood tests and liver and kidney function during drug administration. Generally, the first time chemotherapy, it is recommended to review every 4-7 days, later if stable, side effects are not large, you can consider 7-10 days to review once. The results of the review should be given to the treating doctor in a timely manner so that the chemotherapy dose can be adjusted or the adjuvant therapy drugs can be adjusted according to the results. In severe cases, chemotherapy needs to be stopped, such as severe bone marrow suppression or severe gastrointestinal reactions (e.g. diarrhea, vomiting) or obvious manifestations of peripheral neuritis (numbness in hands and feet, etc.).