Abstract: The present invention provides pharmaceutical compositions containing N-substituted aziridine-2-carboxylic acid derivatives of the general formula: ##STR1## wherein X is a carboxyl, a cyano, an alkoxycarbonyl or an optionally substituted carbamoyl radical, R is a hydrogen atom, an aliphatic hydrocarbon radical which is saturated or can contain one or more unsaturations and can be substituted one or more times by halogen, alkoxy, hydroxyl, dialkylamino, dialkylaminoxy, cycloalkylamino, acylamino, acyl, nitro, alkylthio, alkylsulphinyl, alkylsulphonyl, cyano, carboxyl, alkoxycarbonyl or carbamoyl or by cycloalkyl or cycloalkenyl radicals optionally carrying alkyl, alkoxy or alkoxycarbonyl radicals, optionally interrupted by hetero atoms and optionally bridged, or by an aryl, hetaryl, aryloxy, arylthio, acyloxy, alkoxycarbonylamino or isothioureido radical, or R is a cycloalkyl or cycloalkenyl radical optionally substituted by alkyl, alkoxy or oxo groups, optionally interrupted by hetero atoms and optionally bri

Abstract: The present invention provides pharmaceutical compositions containing N-substituted aziridine-2-carboxylic acid derivatives of the general formula: ##STR1## wherein X is a carboxyl, a cyano, an alkoxycarbonyl or an optionally substituted carbamoyl radical, R is a hydrogen atom, or an optionally substituted aliphatic hydrocarbon radical or cycloalkyl or cycloalkenyl radical, and R.sub.1 is a hydrogen atom or an alkyl or phenyl radical; and the pharmacologically acceptable salts thereof, in admixture with a pharmaceutical diluent or carrier. The present invention also provides, as new compounds, N-substituted aziridine-2-carboxylic acid derivatives of general formula (I') but with the proviso that when X is a carbamoyl or alkoxycarbonyl radical and R.sub.1 is a hydrogen atom, R is not a methyl, ethyl, isopropyl or benzyl radical; and the pharmacologically acceptable salts thereof, and also provides processes for the preparation of these new compounds.