Anemia is a symptom due to lower than normal hemoglobin, not a disease. The reference values for hemoglobin are: 120 – 160g/L for men , 110 – 150g/L for women, 170 – 200g/L for newborns, and less than 100g/L for pregnant women to be considered anemic. Anemia can be accompanied by many diseases, in other words, many factors and diseases can lead to anemia. The common causes of anemia are as follows: 1. Lack of hematopoietic material: the most common type of anemia, such as iron deficiency anemia, malnutrition anemia, etc. 2. Decreased generation: due to bone marrow microenvironment or hematopoietic stem cell function or immune factors, such as aplastic anemia, certain non-hematologic diseases ( 3. Excessive destruction: mainly seen in hemolytic anemia, which is caused by immune factors, red blood cell self factors or mechanical factors leading to red blood cell destruction. 4. Blood loss, trauma, excessive menstruation, etc. If you experience dizziness, weakness, pale face and other anemia symptoms, please consult a doctor promptly to identify the cause and typing and treatment to avoid delaying the disease.