The 5g blood is usually referred to as hemoglobin 5g, which is converted to international units as 50g/L, and is classified as severe anemia. According to hemoglobin concentration, anemia is divided into four degrees, 90-120g/L is mild anemia, between 60-90g/L is moderate anemia, between 30-60g/L is severe anemia, and below 30g/L is very severe anemia, so 50g/L is severe anemia. Clinically, when severe anemia occurs, the patient will show obvious symptoms of anemia, such as pallor, dizziness, fatigue, tinnitus, blurred vision, panic after activity, chest tightness, and a series of symptoms such as insomnia and forgetfulness. Various types of anemia can cause severe anemia, so after the appearance of severe anemia, it is necessary to go to the hospital in time to find out the cause of anemia, and then give the corresponding treatment.