The volume of blood donated refers to the amount of blood given by a healthy citizen at one time when donating blood without compensation. China’s blood donation law stipulates that adults generally donate between 200-400ml of blood. Rarely do they donate more than 400ml, and not less than 200ml. If a person is heavier, he or she can donate up to 400 ml of blood, because the blood volume of the human body is proportional to the body weight, the heavier the body weight, the more blood the human body will have, and donating 400 ml of blood will have no significant effect on the human body. If you are lighter in weight, the amount of blood donated can be reduced accordingly, but generally it should not be less than 200ml, because many clinical blood products are extracted from 200ml of blood, and if it is less than 200ml, it is not very convenient to apply in the clinic. Therefore, the amount of blood donated is usually between 200-400ml, with 300ml-400ml being the most common.