The invention relates to a liquid-crystalline medium having a nematic phase and negative dielectric anisotropy which comprises a) one or more compounds of formula I b) one or more compounds of formula II and c) one or more compounds selected from the compounds of formulae III-1 to III-4 in which the parameters have the meanings indicated herein, to the use thereof in an electro-optical display, particularly in an active-matrix display based on the VA, ECB, PALC, FFS or IPS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of the formula I for the stabilisation of a liquid-crystalline medium which comprises one or more compounds of formula II and one or more compounds selected from the compounds of formulae III-1 to III-4.