Drugs are chemicals that affect the body and brain. Different drugs can have different effects. Some effects of drugs include health consequences that are long-lasting and permanent. They can even continue after a person has stopped taking the substance.There are a few ways a person can take drugs, including injection, inhalation and ingestion. The effects of the drug on the body can depend on how the drug is delivered. For example, the injection of drugs directly into the bloodstream has an immediate impact, while ingestion has a delayed effect. But all misused drugs affect the brain.