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Answer:An active ingredient (also called an active pharmaceutical ingredient, or API) is the drug itself—the part of a medication that does what the product is designed to do. It is intended to provide what is called "pharmacological activity." Active ingredients affect either the structure or the function of the body when given to prevent or treat a disease or health condition. In short, they are the ingredient or ingredients responsible for the therapeutic action of the medication.

Inactive ingredients, on the other hand, are needed to create the medication's formulation—which could be liquid, pill, capsule, or another form. They are not intended to provide any therapeutic action. Also called excipients, inactive ingredients in drugs are the substances that make up the tablet form or the capsule enclosing the medication, for example, or the liquid in which the API is suspended.

A placebo drug, for instance, contains no active ingredients, only inactive ingredients.

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