This document classifies and describes different types of drugs. It discusses drugs based on their use, such as drugs of abuse, drugs of misuse, and pharmaceutical drugs. It also categorizes drugs based on their effects, including hallucinatory drugs, depressants, stimulants, narcotics, and tranquilizers. Various routes of drug administration are outlined, such as topical, oral, rectal, intravenous, intramuscular, subcutaneous, sublingual, and intradermal. Different types of drugs and how they work in the body are defined in detail in the document.