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A substance refers to any material or chemical that can have an effect on the body or mind. It can be natural or synthetic, and it can be ingested, inhaled, or applied externally.
A drug is a specific type of substance that has physiological or psychological effects when introduced into the body.
Toxin: A toxin is a harmful substance produced by living organisms, such as bacteria or plants.
Stimulant: A stimulant is a type of substance that increases activity in the brain and body, leading to heightened alertness and energy levels.