Postoperative gastric cancer patients should go to oncology department or gastroenterology department for chemotherapy, depending on the allocation of the department in the hospital, but basically, they are allocated to oncology department. Chemotherapy is an auxiliary treatment for stomach cancer. If there is no metastasis in gastric cancer patients, chemotherapy is not needed after radical surgery. If there are metastases, adjuvant chemotherapy is needed. Chemotherapy is divided into preoperative, intraoperative and postoperative chemotherapy, which aims to confine the cancer foci, eliminate the remaining cancer foci and prevent recurrence and metastasis of gastric cancer. In case of advanced gastric cancer, chemotherapy is mainly given to alleviate clinical symptoms, improve patients’ quality of life and prolong patients’ life appropriately.