Diseases of the digestive system can lead to high alpha-fetoprotein, such as liver cancer, pancreatic cancer, stomach cancer, intestinal cancer, cirrhosis of the liver, acute and chronic hepatitis, etc. It can also be seen in physiological conditions, such as pregnant women during pregnancy. Alpha-fetoprotein is a glycoprotein, which is mainly synthesized by fetal liver cells and yolk sac. Alpha-fetoprotein is closely related to the development of hepatocellular carcinoma and many kinds of tumors, and it can show high concentration in many kinds of tumors, and can be used as a positive test index for many kinds of tumors. 1. Physiological reasons: alpha-fetoprotein is secreted by newborn naïve liver cells. Fetal liver cells secrete alpha-fetoprotein, which can enter into maternal blood through umbilical cord blood, so alpha-fetoprotein can be high in pregnant women during pregnancy. 2. Tumor: 60%～70% of patients with primary liver cancer have high alpha-fetoprotein, and alpha-fetoprotein of patients with testicular cancer, ovarian tumor, malignant teratoma, pancreatic cancer, gastric cancer, intestinal cancer, lung cancer, etc. can also be high. 3. Benign liver disease: acute and chronic hepatitis, cirrhosis and other benign liver disease patients may have elevated serum alpha-fetoprotein, but most of them are lower than 1000ng/ml, most of them are transient, usually last for 2-3 weeks. Patients with high alpha-fetoprotein should go to the hospital in time to further clarify the cause of the disease and be treated under the guidance of the doctor.