Prophylactic chemotherapy can be done for complete staphylocyes when the patient is determined to have high risk factors for staphylocyes or when follow-up is difficult. The main choices for prophylactic chemotherapy are methotrexate, fluorouracil, and actinomycin D. Single-agent chemotherapy and multiple courses of chemotherapy are given until the patient’s blood chorionic gonadotropin levels fall to normal. The specific dosing regimen is: methotrexate intramuscularly for 5 consecutive days, with a 2nd chemotherapy session two weeks apart. Fluorouracil is used intravenously for 8-10 consecutive days, with a two-week interval for a 2nd chemotherapy treatment. Actinomycin d is given intravenously intravenously for 5 consecutive days with a 2nd chemotherapy treatment two weeks apart. If the patient’s final diagnosis is incomplete hyperemesis gravidarum, prophylactic chemotherapy is not required.