guaco

from The Collaborative International Dictionary of English v.0.48

Guaco \Gua"co\, n. [Sp.] (Bot.)
      (a) A plant ({Aristolochia anguicida}) of Carthagena, used
          as an antidote to serpent bites. --Lindley.
      (b) The {Mikania Guaco}, of Brazil, used for the same
          purpose.
          [1913 Webster]