Nausea and vomiting are common clinical symptoms, mostly associated with digestive system diseases and infectious diseases. However, in clinical practice, nausea and vomiting can often be seen as the first and main symptom of other systemic diseases, which often cause difficulties in diagnosis. 1, endocrine diseases: such as hyperthyroidism, hypothyroidism and hypopituitarism. In clinical work, it is found that thyroid diseases are mostly accompanied by gastrointestinal symptoms such as nausea and vomiting. A patient was admitted to our department with recurrent nausea and vomiting, as well as gallbladder stones and cholecystitis, whose symptoms did not resolve after cholecystectomy in surgery. He was diagnosed with hyperthyroidism in our department, and after treatment, the nausea and vomiting disappeared as the level of thyroid hormones decreased. In the elderly, arteriosclerosis and chronic ischemia of the adenopituitary gland leading to hypopituitarism can also lead to stubborn nausea and vomiting. 2, chronic renal insufficiency: chronic renal insufficiency caused by various reasons, mostly with the first gastrointestinal symptoms. In combination with acute gastroenteritis, it is especially easy to misdiagnose. 3, anemia: nausea and vomiting are the earliest symptoms of chronic anemia and the reason why most patients visit the clinic. Malignant tumors: Many malignant tumors secrete antidiuretic hormone ectopically, leading to the syndrome of dysregulated secretion of antidiuretic hormone (SIADH), especially in lung cancer, and SIADH dilutional hyponatremia can cause persistent nausea and vomiting. A middle-aged male patient with recurrent nausea and dry vomiting after dental veneers was admitted to our department, and no abnormalities were found except for mild hyponatremia after endoscopy, gastrointestinal imaging, abdominal ultrasound, CT and various routine biochemical examinations. He died three months later with a confirmed diagnosis of small cell lung cancer. It can be seen that persistent nausea and vomiting often reflect deep abnormalities of the organism and should be vigilant in clinical work.