The invention relates to 2-oxabicyclo[2.2.1]heptane derivatives of formula I ##STR1## as well as their enantiomers, in which, e.g., A means --(CH.sub.2).sub.n --, (E)-- or (Z)--CH.dbd.CH--, --C.tbd.C, --O-- or --S--,B means hydrogen, C.sub.1 -C.sub.10 alkyl, --OR.sup.2, halogen, --C.tbd.N, --N.sub.3, --COOR.sup.3,R.sup.1 means oxygen or a --CH.sub.2 group, ##STR2## Z means --(CH.sub.2).sub.p --, (E)--CH.dbd.CH--, --C.tbd.C--, W means a direct bond, a free or functionally modified hydroxymethylene group or a free or functionally modified ##STR3## in which the OH group can be respectively in alpha- or beta-position, D means a direct bond, a saturated alkylene group with 1-5 C atoms, a branched saturated or a straight-chain of branched unsaturated alkylene group with 2-5 C atoms,E means a direct bond, --C.tbd.C-- or --CH.dbd.CR.sup.7,R.sup.8 means hydrogen, C.sub.1 -C.sub.10 alkyl, C.sub.3 -C.sub.10 cycloalkyl, optionally substituted C.sub.6 -C.sub.12 aryl or a 5- or 6-member heterocyclic radical, andif R.sup.5 means hydrogen, their salts with physiologically compatible bases, as well as the alpha-, beta- or gamma-cyclodextrin clathrates, as well as the compounds of formula I encapsulated with liposomes, process for their production and the pharmaceutical agents containing these compounds.The compounds are thromboxane antagonists.