The invention is related to substituted 2.beta.-morpholino-androstane derivatives, bonded at their 2.beta.-position to the nitrogen of a group of formula I ##STR1## wherein R represents one to four substituents, each one independently selected from (1-4C) alkyl, phenyl and benzyl, or two at the same carbon atom being together --(CH.sub.2).sub.n -- wherein n is 2-6; and Y is O or S, or a pharmaceutically acceptable salt thereof. These steroids are very potent intravenous anaesthetics. The compounds have fast onset times and ideal `sleep duration` vs. `recovery to full coordination` profiles.
Steroids of the androstane series having a 3.alpha.-hydroxy group, a 3.beta.-hydrogen or methyl group; a 10-hydrogen atom or methyl group, an 11-oxo group or two hydrogen atoms at the 11-position, a 17.alpha.-hydrogen atom, and a group at the 17.beta.-position which is esterified carboxyl group, an N-mono or di-substituted carbamoyl group, a cyano group, a formyl group or an acetalised formyl group; and the 3.alpha.-esters thereof. The steroids possess anaesthetic properties.