Source : Webster's Revised Unabridged Dictionary (1913)

Lactifuge \Lac"ti*fuge\, n. [L. lac, lactis, milk + fugare to
   expel.] (Med.)
   A medicine to check the secretion of milk, or to dispel a
   supposed accumulation of milk in any part of the body.

Source : WordNet®

lactifuge
     n : any agent that reduces milk secretion (as given to a woman
         who not breast feeding)