What do we call a chemical that originates outside the body?

A chemical that originates outside the body is referred to as an exogenous chemical. This term is used to describe substances that enter the body from the external environment, as opposed to endogenous chemicals, which are produced within the body itself. Exogenous chemicals can include a wide range of substances, such as nutrients, drugs, and pollutants, and they can have various effects on biological processes. Understanding the distinction between exogenous and endogenous is important in various fields, including medicine and toxicology, as it helps to determine how these substances interact with biological systems and influence health.