any substance that adulterates (lessens the purity or effectiveness of a substance); "it is necessary to remove the adulterants before use"

making impure or corrupt by adding extraneous materials; "the adulterating effect of extraneous materials"

Substance added to heroin after the heroin conversion process is completed. Adulterants are pharmacologically active. Quinine and procaine are typical adulterants added to heroin.

A substance, either a biologically active material such as another drug or an inert material, added to a drug when it is formed into a tablet or capsule.

An adulterating substance.

Adulterants are chemical substances which should not be contained within other substances (eg. food, beverages, fuels or pesticide) for legal or other reasons. Adulterants may be intentionally added to substances to reduce manufacturing costs, or for some deceptive or malicious purpose. Adulterants may also be accidentally or unknowingly introduced into substances.