Corticoid 17-alkyl carbonate 21-carboxylic and carbonic esters of the formula I ##STR1## are described in which A is CHOH and CHCl, CH.sub.2, C.dbd.O or 9(11) double bond; Y is H, F or Cl; Z is H, F or CH.sub.3 ; R(1) is aryl or hetaryl; n and m are zero or 1; R(2) is alkyl or --(CH.sub.2).sub.2 --OCH.sub.3 ; R(3) is H or methyl. They are obtained by reacting a compound of the formula II, ##STR2## in which R(5) is OH, with an activated carboxylic acid of the formula III, The compounds I have a very strong local and topical antiinflammatory action and exhibit a very good ratio of local to systemic antiinflammatory effects, which ratio is often markedly superior to that of analogous corticoid 17-alkyl carbonate 21-esters which do not carry any aryl or heteraryl group in the 21-ester radical.