Severe anemia is not suitable for gastroscopy and carries certain risks. Anemia is a clinical condition in which the volume of red blood cells in the human peripheral blood is reduced below the lower limit of the normal range. Hemoglobin less than 60g/L is considered as severe anemia. 1. Severe anemia is mainly manifested by dizziness, headache, insomnia, palpitations (rapid heartbeat, often accompanied by panic), increased heart rate, chest tightness, shortness of breath, abdominal distension, and decreased appetite. When the patient has these symptoms, his body can not tolerate the damage caused by gastroscopy, so it is not suitable for patients with severe anemia to do gastroscopy, and there is a possibility of fainting during the examination, or even life-threatening. 2. Patients with moderate-to-severe anemia may also overdose because anemia reduces the binding of drugs to plasma proteins and increases the effectiveness of the drugs, so there is a high risk of anesthesia, which is a relative contraindication to painless gastroscopy. Patients with severe anemia should replenish blood volume in time to correct the anemia, and wait for the body to recover before going for the next examination and treatment. If the above symptoms occur, it is recommended to go to the hospital in a timely manner, under the guidance of the physician early formal treatment.