Background <p>Phytohormones as indole-3-propionic acid (IPA) and indole-3-butyric acid (IBA) are commonly used in several agricultural purposes. Some negative effects may have appeared due to their uses to mammals. So, their mammalian side effects were studied.</p> Methods <p>IPA and IBA were obtained in technical grade. Their structures were confirmed by melting point, elements analysis (C, H, N) and UV, IR, ¹HNMR and mass spectroscopy measurements. The biological effects of both IPA and IBA on the pregnant white mice females (<i>Mus musculus</i> var. <i>albus</i>) at sublethal doses (5, 25, 50 and 100&#xa0;mg/kg body weight) at the first, second and third weeks of gestation periods as well as their embryocidal and teratogenic effects were studied. Untreated pregnant mice females were concurrently used as control.</p> Results <p>The results indicated that both IPA and IBA had destroying effects on the formation and development of the embryos at all the tested doses with treatments during the three weeks of gestation periods of mice. Administration of both IPA and IBA led to the formation of large amounts of fats inside and around the uterus which were able to ruin embryos completely in addition to resorption of embryos due to bleeding inside the uterus. IBA proved to be more active as embryocidal than IPA which may be due to IBA itself in addition to the dual effect of IBA and its metabolite IAA.</p> Conclusion <p>IPA and IBA that are using in agricultural aspects should be used under precautions. The treated food should not be used for feeding the pregnant women; otherwise, malformation or even abortion of their fetuses might occur.</p>