NEW MATERIAL:The compound of formula I [A is group of formula II or formula III; R1 is H or OH; R2 is H, OH, lower alkanoyloxy, etc.; R3 is H, lower alkanoyloxy or tri(lower alkyl)silyloxy; R1, R2 and R3 are not H at the same time].

EXAMPLE: A-Homo-5,14-hydroxy-3-oxa-5β,14β-cardo-20(22)-enoild-3a-one.

USE: A cardiotonic agent. It increases the myocardial contraction, and is useful for the remedy of e.g. congestive failure. It has no influence to the pulse rate and has low side effect.

PREPARATION: The compound of formula I is produced by reacting the compound of formula IV (R4 or OH or oxo) with a peracid (e.g. perbenzoic acid, m-chloropherbenzoic acid, etc.) in a solvent such as chloroform, benzene, etc. at room temperature W the refluxing temperature of the solvent, preferably at room temperature W70°C.