Marsdenia tinctoria, a perennial climber has been used by the Shautal of Bangladesh to induce abortion. Bio-activity directed phytochemical investgation revelaed that the plant contained tinctoramine, a new steroidal alkaloid and tinctoralactone, a novel steriod as the active constituents. Both the compounds showed oxytocic, antiimplantation and abortifacient activities in mice and rats. The alkaloidal fraction, which contained tinctoramine and tinctoralactone, did not have any adverse effect on SGOT, SGPT, BUN and serum albumin when administered to rats and mice. The structures of the compounds were elucidated by spectral studies (UV, IR, 1H NMR and Mass) of these and related compounds isolated from plants of genus Marsdenia. © 1994 IUPAC