Therapeutic abortion is proposed when a pregnancy threatens a woman s life and the fetus is not viable ex utero. As the intention is not to kill the fetus, this action should be named "therapeutic interruption of pregnancy". However, in some cases the fetus directly hampers the mother s health. Thus, the removal of the cause of the disease coincides with killing the fetus. Therapeutic abortion has been proposed for several situations. A) When pregnancy and not the fetus, impairs maternal life (e.g ovular infection, ectopic pregnancy, decompensation of a preexisting disease or diseases of pregnancy as pre-eclampsia/eclampsia, HELLP and Ballantyne syndromes, choriocarcinoma). B) A risk for maternal survival caused by the embryo or fetal genetic constitution: autoimmune diseases of the mother generated by fetal antigens, some types of eclampsia with or without HELLP syndrome due to an immune or exaggerated inflammatory response of the mother, Ballantyne syndrome associated to eclampsia due to fetal-maternal genetic incompatibility, the classic fetus-maternal genetic incompatibility, embryo or fetus diseases caused by their genomic constitution, mainly hydatidiform mole and the triploid, or fetal cancer. Scientifc knowledge and a prudential Medical Ethics are capable to solve most cases (Rev Méd Chile 2003; 131: 562-8).