Disclosed are cardiotonic medicines containing, as the active ingredient, at least one of compounds of formula (I) and their pharmacologically acceptable salts when they form salts. ##STR1## wherein X.sup.1 and X.sup.2 do not exist or represents an oxygen atom; A represents OH or a C.sub.1 -C.sub.4 acyloxy group; B represents a hydrogen atom or may form a chemical bond along with A; X is an oxygen atom, nitrogen, sulfur, etc.; R.sup.1 and R.sup.2 each represents a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group, etc.; R.sup.3 and R.sup.4 each represents a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group, etc., or they may together form a 1,4-butylene or 1,5-pentylene group. The compounds have a strong activity of reinforcing the contraction of cardiac muscles and a strong activity of reducing the rate of heart beats. As they are not toxic, they are useful as cardiotonic medicines.