Generally speaking, it is appropriate to donate around 300mL of blood for the first time. China’s blood donation law stipulates that healthy citizens should donate between 200-400mL when donating blood. However, for a first time donor, it is better to donate 300mL of blood, and the amount of blood donated should preferably be estimated according to one’s own weight, because the amount of blood in one’s body is proportional to one’s own weight, and the weight of one’s own blood accounts for about 7%-8% of one’s weight. A healthy adult weighing about 70 kg donates 300 mL of blood, which is less than 1/12 of the total blood volume of the whole body, and has no significant impact on the body and will not show obvious symptoms of anemia, so it is more appropriate to donate 300 mL. For lighter weight women, such as those weighing around 50kg, the amount of blood donated for the first time can also be around 200mL, as the amount of blood donated will not cause any obvious discomfort either. Therefore, it is important to estimate the appropriate amount of blood to donate for the first time, taking into account your own weight.