A compound selected from the group consisting of all enantiomeric and diastereoisomeric forms of a decahydroquinoline of the formula ##STR1## wherein R.sub.1 is alkyl of 1 to 5 carbon atoms, R.sub.2 is selected from the group consisting of hydrogen and akyl of 1 to 5 carbon atoms, A is selected from the group consisting of --(CH.sub.2).sub.n --, --CH.sub.2 O-- and alkylene substituted with alkyl having a total of 2 to 8 carbon atoms, n is an integer from 0 to 5, Z is selected from the group consisting of optionally substituted phenyl, optionally substituted naphthyl, optionally substituted indenyl, optionally substituted heteromonocycle of 5 to 6 members and optionally substituted heterobicycle with the proviso that when Z is o-alkoxy-phenyl, A is not --(CH.sub.2).sub.n -- in which n is O, and their non-toxic, pharmaceutically acceptable acid addition salts and their quaternary ammonium salts and intermediates having analgesic, diuretic, hypotensive, anti-arrithmic and anti-cerebral-ischaemic properties.