Whether you are donating blood for the first time or repeatedly, you will experience mild pain. Because of the need to do venipuncture when donating blood, the staff will pierce the needle of the blood donation needle into the peripheral vein of the donor, and the blood in the vein will continuously enter into the blood donation bag to be stored, which is the whole process of blood donation. Because of the need to puncture the vein, the peripheral veins of the human body are richly distributed with nerve endings, when stimulated will produce a certain degree of pain. Moreover, the needle of the blood donation needle is thicker than the diameter of a normal injection needle, so the trauma to the human body is greater than a normal intramuscular injection, and the pain may be more intense. However, adults are generally able to tolerate the pain, and the pain gradually disappears after the needle is withdrawn. Therefore, no matter which time you donate blood, you will experience mild pain, but you can tolerate it.