The Collaborative International Dictionary of English v.0.48:

Cureall \Cure"*all`\ (k?r"?l`), n.
   A remedy for all diseases, or for all ills; a panacea.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cure-all
    n 1: hypothetical remedy for all ills or diseases; once sought
         by the alchemists [syn: panacea, nostrum, catholicon,
         cure-all]