An adulterant is a chemical substance which should not be contained within other substances (eg. food, beverages, fuels for legal or other reasons). Adulterants may be intentionally added to more expensive substances to increase visible quantities and reduce manufacturing costs or for some other deceptive or malicious purpose. Adulterants may also be accidentally or unknowingly introduced into substances. The addition of adulterants is called adulteration.
The word is only appropriate when the additions are unwanted by the recipient, otherwise the expression would be food additive. Adulterants when used in illicit drugs are called cutting agents, while deliberate addition of toxic adulterants to food or other products for human consumption is known as poisoning.
