The Collaborative International Dictionary of English v.0.48:

Febrifuge \Feb"ri*fuge\, n. [L. febris fever + fugare to put to
   flight, from fugere to flee: cf. F. f['e]brifuge. see
   Febrile, Feverfew.] (Med.)
   A medicine serving to mitigate or remove fever. -- a.
   Antifebrile.
   [1913 Webster]

WordNet (r) 3.0 (2006):

febrifuge
    n 1: any medicine that lowers body temperature to prevent or
         alleviate fever [syn: antipyretic, febrifuge]