Abstract: Prostaglandin analogues of the formula: ##STR1## wherein A represents a grouping of the formula: ##STR2## X represents ethylene or cis-vinylene, Y represents ethylene or trans-vinylene, R.sup.1 represents a straight- or branched-chain alkyl group containing from 4 to 10 carbon atoms, and R.sup.2 represents a hydrogen atom or a straight- or branched-chain alkyl group containing from 1 to 12 carbon atoms and cyclodextrin clathrates of such acids and esters and, when R.sup.2 represents a hydrogen atom, non-toxic salts thereof, the bonds attaching the epidithio radical to the carbon atoms in the 9- and 11-positions in the grouping of formula VA being either botn in .alpha.-configuration or both in .beta.-configuration are disclosed.These compounds exhibit characteristic prostaglandin properties.