An abortifacient is a substance that induces abortion. Abortifacients for animals that have mated undesirably are known as mismating shots.
Common abortifacients used in performing medical abortions include mifepristone, which is typically used in conjunction with misoprostol in a two-step approach.There are also several herbal mixtures with abortifacient claims, though there is no available data on the efficacy of these plants in humansMifepristone, a progesterone receptor competitive antagonist, was first approved in 1988 under the trade name Mifegyne for medical termination of early pregnancy in conjunction with a prostaglandin analogue. Mifepristone, also known as RU-486, is marketed under the trade name Mifegyne in France and countries other than the U.S., and under the trade name Mifeprex in the U.S.
Misoprostol, a synthetic prostaglandin E1 （PGE1） analogue, was first approved in 1988 under the trade name Cytotec for reducing the risk of NSAID-induced gastric ulcers. Misoprostol is approved in France under the trade name GyMiso for use with mifepristone for medical abortion. Misoprostol is used off-label with mifepristone for medical abortion in the U.S.
Misoprostol alone is sometimes used for self-induced abortion in Latin American countries where legal abortion is not available, and by some people in the United States who cannot afford a legal abortion.