Clinical regulations stipulate that anemic people are not suitable for blood donation, and if anemic people donate blood, they will often bring more serious effects to themselves. Common manifestations include: First, more severe pallor, more pronounced headache and dizziness, and more likely to have a series of neurological symptoms such as heartburn and chest tightness, tinnitus and blurred eyes, insomnia and forgetfulness. Second, the ability to exercise is more reduced. After the patient’s anemia and blood donation, the symptoms of limb weakness are more obvious, and the limbs are more likely to be weak after activity, and need to stop and rest, and then the symptoms of double limb weakness will appear when walking again. Third, the burden on the cardiovascular system is heavier. Patients with anemia are more likely to have palpitations, chest tightness and shortness of breath after blood donation, and they will feel panic and chest tightness after slight activities, and even need to be relieved by oxygen in severe cases.