1,3-Benzodioxaneprostanoic acid compound of the formula ##STR1## wherein R.sub.1 is hydroxy, alkoxy of 1-10 carbon atoms, methylsulfamido, substituted or unsubstituted aryloxy, or O--CH.sub.2 --U--V wherein U is a direct bond, carbonyl, or carbonyloxy, and V is phenyl or phenyl substituted, e.g. by one or more of phenyl, phenoxy, alkoxy of 1-2 carbon atoms, and halogen; A is --CH.sub.2 --CH.sub.2 -- or trans --CH.dbd.CH--; B is --CH.sub.2 --CH.sub.2 -- or cis- or trans--CH.dbd.CH--; Z is hydroxymethylene or carbonyl; X Y, if Z is hydroxymethylene, is ##STR2## or, if Z is carbonyl, is ##STR3## or --CH.dbd.CH--; R.sub.2 is hydrogen or alkyl of 1-5 carbon atoms; R.sub.3 and R.sub.4 each are H, F, Cl, Br, I or CF.sub.3, CH.sub.3 or alkoxy of 1-2 carbon atoms or R.sub.3 and R.sub.4 in 6-,7-position is methylendioxy; and if R.sub.1 is hydroxy, salts thereof with pharmaceutically acceptable bases, are agents for inducing menstruation, interrupting pregnancy, inducing labor and synchronizing the sexual cycle in female mammals.