China’s blood donation law advocates healthy citizens to donate blood without compensation, and also clearly stipulates that the interval between healthy citizens donating blood cannot be less than 6 months, i.e. healthy citizens can donate blood again after an interval of 6 months, because the regular blood donation volume is between 300-400ml, and the body loses 300-400ml of blood after donating blood. This includes all kinds of blood cells, with red blood cells, white blood cells, and platelets. It also includes the lost plasma, including water, inorganic ions, albumin, globulin and various clotting factors, etc. The recovery of these blood components takes different times and the recovery time varies in length. For example, the recovery time of water is the fastest, and the recovery time of white blood cell platelet is also faster, generally in about a week. However, the recovery time of red blood cells is slower, because the normal life span of red blood cells is about 120 days, which is about 4 months before the number of red blood cells can return to the level before blood donation. Therefore, in order to ensure the health of citizens and the quality of blood, China has set the interval between blood donations at 6 months.