Drugs can only be absorbed into the human body to play a therapeutic role, the method of drug entry into the body is called the route of administration, commonly used routes of administration are oral, sublingual, rectal, skin mucosal administration, inhalation, injection, etc. Oral route of administration is very common. Sublingual administration, for example, when angina attacks, nitroglycerin tablets are held under the tongue and allowed to dissolve and be absorbed naturally. Rectal administration, such as inserting a fever suppository into the rectum through the anus, slowly melting and being absorbed by the rectal mucosa. Skin and mucous membrane administration, such as the application of topical ointment for skin diseases, eye drops, ear drops, nasal drops, etc. Inhalation administration, such as nebulized inhalation of asthma medication during an asthma attack. Injection administration, including intradermal injection, such as penicillin skin test; subcutaneous injection, such as insulin; intramuscular injection, such as intramuscular injection of penicillin in the buttocks; intravenous injection: including intravenous push and intravenous drip, intravenous push, such as hypoglycemia with a syringe to push glucose into the blood vessels; intravenous drip is also commonly known as a hanging injection.