The patient had nausea, nausea and foreign body sensation in the throat for 4 months. More than a month ago, the patient visited the doctor with these symptoms. The ENT doctor diagnosed the patient as having left vocal cord paralysis, and the gastroenterologist diagnosed the patient with “gastroesophageal reflux and chronic superficial gastritis” after a gastroscopic examination. The patient was seen again and I carefully reviewed the patient’s medical records and found that although the patient’s nausea was severe, the doctor only checked the transaminases but not the bilirubin when he gave the patient the laboratory tests. On examination, I found that the patient’s face was somewhat yellow. Since the patient had already eaten and blood could not be collected, I first had the patient undergo a routine urine test, which showed that the patient’s urine bilirubin and urine bilirubin were both positive, indicating the presence of jaundice. The next day, the patient’s blood tests showed normal transaminases, normal renal function, and mildly elevated serum direct and indirect bilirubin. Since the patient’s hepatocyte enzymes and bile duct enzymes were normal and the jaundice was manifested by elevated direct and indirect bilirubin, I prescribed an ultrasound test for the patient on the one hand and considered that it was likely that the patient had mild hemolysis, which is most commonly seen in megaloblastic anemia, and examined the patient’s lid conjunctiva, which was slightly pale. The patient’s hemoglobin was 90 g/L, and he showed macrocytic anemia with varying red blood cell sizes and some lightly stained cell centers. In megaloblastic anemia, the patient could show nausea and poor appetite. Thereafter, the patient was tested for serum iron, folic acid and vitamin B12 levels, and a bone marrow examination was performed on the patient. The results of the bone marrow aspiration showed that the patient had cellular anemia, and the serum tests suggested that the patient was also considered deficient. The patient was carefully questioned about the fact that the patient usually eats less meat foods and had been affected by mouth ulcers for 1 month before the onset of the disease. Therefore, the patient’s folic acid deficiency might be related to the patient’s low food intake. As the patient’s folic acid deficiency gradually worsened, it led to the patient’s nausea and poor nausea, which, together with the acid suppressant treatment the patient received, affected the absorption of nutrients, thus leading to the patient’s symptoms getting worse. In order to exclude other causes of nutrient deficiency, the patient was also tested for relevant tumor-related tests, which had no positive findings. After the patient was treated with folic acid and vitamin B12, the patient’s symptoms were quickly relieved, his appetite turned better, the foreign body sensation in his throat disappeared, and his hemoglobin level quickly returned to normal. As a clinician, when the specialties become more and more subdivided, one cannot only think of the diseases related to one’s own specialty; the patient is a whole, not an individual organ or system, and detailed history questioning and careful examination and observation are very important for a comprehensive understanding of the patient’s condition and judgment.