xenobiotics are substances foreign to an entire biological system. They are artificial substances, which did not exist in nature before their synthesis by humans. The term originates from Greek, meaning foreigner, stranger.
xenobiotic that have estrogenic effect is named xenoestrogen. Their effect is based on their ability to bound to human (or animal) estrogen-receptors. Amongst xenoestrogens pesticides, industrial chemicals and additives as well as pharmaceutical substances can be found.