The angle of the intramuscular injection should be 90°, and it should be rapidly inserted into the muscle to a depth of about 2/3 of the needle stem. 1. The general requirement for intramuscular injection is that the needle should be at a right angle to the muscle, which enables the needle to be rapidly inserted into the muscle and reduces the patient’s pain. The depth of the needle is about 2/3 of the needle stem, about 2.5~3cm. 2. Commonly used intramuscular injection sites include the gluteus maximus, gluteus medius or deltoid muscles, etc., with the gluteus maximus being the most commonly used for local injection. The injections should be performed without blood return to prevent the drug from being mistakenly introduced into the blood vessels, resulting in toxic reactions. In addition to intramuscular injection, it also includes intradermal injection and intravenous injection, etc. The injection should be carried out by a professional doctor, and try not to take a bath after the injection to avoid infection of the needle eye.