Source : Webster's Revised Unabridged Dictionary (1913)

Alleviator \Al*le"vi*a`tor\, n.
   One who, or that which, alleviates.

Source : WordNet®

alleviator
     n 1: a therapist who makes suffering more endurable
     2: remedy that alleviates pain without curing [syn: {palliative},
         {alleviant}]