Nausea without appetite may be a normal physiological phenomenon, or it may be a manifestation of certain diseases, such as pregnancy, acute gastroenteritis, anorexia, liver function impairment, etc. 1. Normal physiological phenomenon: as the temperature rises in summer, the patient will have nausea and lack of appetite without other abnormal symptoms, which is a normal physiological phenomenon. 2. Pregnancy: women of pregnancy age experience delayed menstruation, causing loss of appetite and nausea, which is an early pregnancy reaction. 3. Acute gastroenteritis: gastrointestinal infections caused by eating unclean food, patients may experience nausea and lack of appetite, often accompanied by diarrhea, vomiting and other symptoms. 4. Anorexia: patients are worried about eating food that leads to obesity, boredom of eating, excessive dieting, etc. Anorexia is gradually triggered, and nausea and lack of appetite will occur every time they see food, especially greasy and fatty food. 5. Liver function damage: Liver function damage due to various reasons, the function of the liver is reduced, the function of toxin removal is also reduced, the alanine aminotransferase appears to be elevated, which causes nausea, loss of appetite, fatigue and other symptoms. There are many other causes of nausea and lack of appetite, it is recommended that patients go to the regular hospital in time, after clarifying the cause of the disease, under the guidance of the doctor to carry out targeted treatment or treatment, in order to reduce the adverse effects of the disease.