How long chemotherapy is needed for malignant ovarian teratoma is determined primarily by the degree of malignancy. If the degree of malignancy is high, generally need 6-8 courses of treatment, if the degree of malignancy is relatively low, generally need 3-4 courses of treatment. 1. Higher degree of malignancy: 6-8 courses of chemotherapy are usually needed, with an interval of 3 weeks between each course, only enough courses can kill the cancer cells in the body. 2. Less malignant: Usually 3-4 courses of chemotherapy are needed, and one course of chemotherapy takes 3-4 days. However, follow-up examinations are needed after the courses of chemotherapy. Chemotherapy is usually started one month after the surgery. In addition to the degree of malignancy of ovarian teratoma, it also needs to be decided according to one’s own condition and tolerance, if the physical condition is poor and tolerance is weak, it is recommended to postpone the chemotherapy time. The specific duration of chemotherapy is recommended to be decided under the guidance of professional doctors in combination with their own conditions.