There is not much difference between donating 200mL of fresh blood and 400mL of fresh blood for a healthy adult. First of all, for a healthy adult, the amount of blood donated at one time should be 200 mL, not more than 400 mL. The total normal blood volume of an adult is about 4000-5000 mL, so even if you donate 400 mL of blood, it only represents about 10% of your body’s blood donated, which generally does not have too much negative impact on your body. Secondly, donating 400mL of blood is more likely to stimulate the hematopoietic function of the bone marrow and the neuroendocrine regulation function compared to donating 200mL of blood. Blood donation promotes the regeneration of fresh blood and replenishes blood volume, while also helping to strengthen the body. In addition, for those who donate 400mL of blood, the recovery time will be relatively longer. Individuals who donate too much blood will also experience transient symptoms of reduced blood volume, such as dizziness, weakness, and pallor, which will usually gradually return to normal within a few days. It is recommended that people who have just donated blood should take more rest and minimize heavy physical labor and strenuous exercise. It is also recommended that people who have just donated blood should take rest and minimize heavy physical work and strenuous exercise. They should also pay attention to protein, iron, folic acid and vitamins in their diet to help their body recover.