Medicinal substances used to diagnose, treat, or prevent disease.

• Pharmaceutical compounds supplied for therapeutic use.

Psychoactive substances used recreationally, often illegal and addictive.

• Illicit narcotics or stimulants such as cocaine or heroin.

Third-person singular of drug: administers a drug to impair or sedate.

• Secretly adds a drug to someone's food or drink.

Third-person singular of drug: gives or prescribes medication as treatment.

• Administers pharmaceutical drugs under medical supervision.