Possible causes of nausea include pregnancy reaction, chronic gastritis, hepatobiliary system diseases and renal insufficiency. 1. Pregnancy reaction: If a woman of childbearing age suddenly has no appetite and a little nausea, it may be an early pregnancy reaction, which usually occurs between 1 and 2 months after menopause. Blood test for human chorionic gonadotropin (HCG) is obviously elevated, and ultrasound examination of the uterus with a pregnancy sac can be clear. There is no need for any treatment at this time, and the symptoms of pregnancy reaction will gradually disappear after 2 to 3 months. 2. Chronic gastritis: patients with chronic gastritis often suffer from loss of appetite, indigestion and sometimes bloating, abdominal pain and nausea, in which case gastroscopy is performed to make a clear diagnosis. 3. Hepatobiliary system diseases: such as chronic cholecystitis, viral hepatitis, etc. Hepatobiliary system diseases will be accompanied by vague discomfort in the right upper abdomen, loss of appetite, nausea, anorexia and other symptoms. Ultrasound examination of liver and biliary system and liver function test can make a clear diagnosis, and follow the doctor’s instructions to use drugs to treat the original disease. 4. Renal insufficiency: patients may also have gastrointestinal reactions, such as loss of appetite, nausea, vomiting and so on. A little nausea without appetite may also be due to other reasons, it is recommended that patients go to the hospital in a timely manner to improve the examination, a clear diagnosis, under the guidance of the doctor for treatment.