In order to bring down the AFP, it is necessary to first know the cause of the elevated AFP and treat the cause, and the AFP can usually drop accordingly. In the fetal period the value of AFP is very high, basically it can drop to a very low state in 2-3 months after birth, and normally AFP is rarely measured in adults. Elevated alpha fetoprotein can occur in primary liver cancer, malignant tumors of the gonads, pancreatic cancer, gastric cancer, viral hepatitis and cirrhosis of the liver, among which patients with viral hepatitis or cirrhosis can use drugs to protect the liver and treat hepatitis, thus lowering alpha fetoprotein. As for other neoplastic diseases, such as primary liver cancer, malignant tumor of gonad, pancreatic cancer and gastric cancer, the treatment methods are as follows: 1. Primary liver cancer: early stage primary liver cancer can be surgically removed and the alpha fetoprotein can be reduced to normal after surgery. For patients with advanced liver cancer who cannot receive surgery, targeted therapy or immunotherapy can be used to control the development of liver cancer, and the level of methemoglobin can gradually decrease after effective treatment; 2. gonadal malignant tumors: early gonadal malignant tumors can be removed by radical surgery and postoperative adjuvant chemotherapy and radiotherapy, and methemoglobin can be reduced to normal through comprehensive treatment means. In case of advanced gonadal malignant tumor, systemic chemotherapy can be used to control the disease, and the fetoprotein can gradually decrease after effective treatment, and the cancer foci can even disappear completely after combined chemotherapy, at which time the fetoprotein can be reduced to normal; 3. If the patient is in advanced stage and cannot be removed surgically, he can undergo palliative treatment such as radiotherapy, which can bring down the fetoprotein in patients with effect; 4.Gastric cancer: early stage of gastric cancer can be removed surgically and the fetoprotein can be reduced to normal. If it is a patient with progressive gastric cancer, a comprehensive treatment mainly based on surgery and supplemented by radiotherapy and biological targeted therapy can be adopted to prolong the survival of patients, and patients with effective treatment can have their methemoglobin decreased.