Xenobiotic metabolism
Xenobiotic metabolism (from the Greek xenos "stranger" and biotic "related to living beings") is the set of metabolic pathways and enzymatic defense mechanisms that transform and eliminate xenobiotics, compounds foreign to an organism's normal biochemistry, such as pollutants, natural toxins, dietary constituents, and synthetic chemicals. These pathways are a form of biotransformation found in bacteria, plants, fungi, and animals, and are considered to be of ancient evolutionary origin as defenses against naturally occurring chemical stressors.