There are the following precautions for the first time blood donation: sufficient rest, light diet, moderate amount of water, avoid taking drugs, etc. before blood donation. After blood donation, the blood of human body is less than the normal physiological amount in a short period of time, at this time, the immunity of the donor will be relatively reduced, so the donor should have sufficient rest before blood donation, so as to ensure good physical strength, and increase nutrition to promote bone marrow hematopoiesis, so that the blood in the body will be restored to the normal physiological amount. Before donating blood, you should have a light diet, drink an appropriate amount of water, avoid spicy and greasy food, and also avoid smoking and drinking alcohol, so as not to affect the quality of blood. Don’t be nervous when donating blood, rest appropriately after donating blood, and don’t do strenuous activities. You should not take medication before blood donation, otherwise the medication components will appear in the blood, and the blood will not meet the standard and can not be used for clinical treatment.