The Collaborative International Dictionary of English v.0.48:

Cauterant \Cau"ter*ant\, n.
   A cauterizing substance.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cauterant
    n 1: an instrument or substance used to destroy tissue for
         medical reasons (eg removal of a wart) by burning it with a
         hot iron or an electric current or a caustic or by freezing
         it [syn: cautery, cauterant]