Once chemotherapy is started means that the tumor has shown indications for chemotherapy, i.e. indications for tumor chemotherapy, it does not mean the condition is good or bad. Some tumors have better effect after chemotherapy, which can moderately alleviate the tumor development and shrink the tumor to facilitate better tumor removal during surgery, and post-operative chemotherapy can help clean up the residual tumor cells in the body and delay the recurrence of tumor. For solid tumors, such as skin cancer, small cell lung cancer and ovarian cancer, the effect is generally better after chemotherapy, and consolidation therapy is also better for patients after surgery and local radiotherapy for solid tumors, as well as for patients with recurrence and dissemination after surgery or radiotherapy. For postoperative patients it can improve the quality of survival, and prolong the survival period. However, the side effects of chemotherapy should also be highly noted. While killing tumor cells, chemotherapy drugs can cause damage to normal body cells to varying degrees, and non-specific adverse symptoms such as nausea, vomiting, decreased white blood cells, anemia, decreased platelets, etc. can occur. When the side effects cause more harm to the patient, chemotherapy should be stopped in time and treated with drugs to raise white blood cells and antiemetic, etc. After the situation improves, chemotherapy should be continued according to medical advice.