High gastrin may be caused by autoimmune gastritis, chronic renal insufficiency, gastrinoma and other factors. 1. Autoimmune gastritis: When autoimmune gastritis occurs, the body will produce anti-mural cell antibodies, and the mural cells can secrete hydrogen ions. The reduction of hydrogen ions in the body can feedback cause G cells to secrete gastrin, and high gastrin may also occur. 2. Chronic renal insufficiency: the kidneys can inactivate gastrin, and when chronic renal insufficiency occurs, this inactivation may be weakened, resulting in high gastrin. 3. Gastrinoma: Gastrinoma is a kind of neuroendocrine tumor, which can secrete gastrin. When gastrinoma occurs, it may also lead to high gastrin. When gastrin is high, you should seek medical treatment in time, clarify the cause of the disease under the guidance of the doctor, and treat it actively.