The length of a course of chemotherapy needs to be judged according to the type of tumor and the overall situation of the patient, and cannot be generalized. Generally speaking, most chemotherapy is usually given in a 3-week cycle, and the treatment takes about 5-7 days, with a rest period of about 14 days, before moving on to the next cycle of chemotherapy. Simply speaking, the length of a course of chemotherapy mainly depends on the chemotherapy regimen. Doctors will choose the appropriate course and cycle of chemotherapy according to the patient’s tumor type, considering the effect of chemotherapy drugs on the proliferation phase and killing power of tumor cells, and combining with the patient’s individual tolerance, etc., in order to prevent the chemotherapy drugs from accumulating in the patient’s body insufficiently or excessively, which may affect the efficacy and even lead to the occurrence of adverse events. In conclusion, the course of chemotherapy varies for different tumor patients. It is recommended that patients must pay attention to actively cooperate with chemotherapy, strictly follow the doctor’s instructions and treat regularly with a full course of chemotherapy. If some adverse reactions occur during chemotherapy, such as nausea and vomiting, some antiemetic drugs can be taken under the guidance of doctors, and diet can also be used to regulate them.