The latest days that chemotherapy for breast cancer can be postponed varies from person to person, but it is suggested that it should not be more than one week or so. Chemotherapy generally needs to be treated according to the schedule, with every 21 days as a cycle, and the time of chemotherapy can be extended appropriately according to the difference of chemotherapy protocols, toxicity and side effects, the number of cycles of chemotherapy, and the difference of the patient’s physical condition. There will be some side effects during and after chemotherapy, the common ones are nausea, vomiting, loss of appetite, bloating, constipation, etc. However, the side effects caused by chemotherapy drugs will be gradually reduced 3-5 days after the end of chemotherapy. Breast cancer chemotherapy is generally 21 days as a cycle, if the patient’s physical condition can be, it is recommended to carry out chemotherapy on time, but if the body is intolerant of the situation can be postponed, the general postponement time is best not to be more than a week or so, control within 28 days. Usually should pay attention to relaxation, eat more light food. Specifically for each patient, whether to delay chemotherapy, it is best to let the competent doctor to evaluate and give guidance.