Chemotherapy is useful for bowel cancer, especially for stage III bowel cancer and stage IV bowel cancer. Stage I and II bowel cancers depend on the specific situation, stage I does not need chemotherapy, while stage II bowel cancers need postoperative adjuvant chemotherapy if combined with high-risk factors, such as tumors of T3 and T4, as well as vascular thrombus and microsatellite stability. Stage III bowel cancer refers to the combination of lymph node metastasis, chemotherapy can reduce postoperative recurrence and prolong postoperative progression-free survival time. In advanced colorectal cancer, palliative chemotherapy can have the effect of alleviating symptoms or pain, such as metastasis to lungs or liver, which can make the tumor shrink after chemotherapy and win the chance of surgical resection for patients. Therefore, chemotherapy for bowel cancer is a very important means.