Amyl nitrite

from The Collaborative International Dictionary of English v.0.48

Nitrite \Ni"trite\, n. [Cf. F. nitrite. See {Niter}.] (Chem.)
   A salt or ester of nitrous acid; a compound bearing the
   {-NO2} radical.
   [1913 Webster +PJC]

   {Amyl nitrite}, a yellow oily volatile liquid, used in
      medicine as a depressant and a vaso-dilator. Its
      inhalation produces an instantaneous flushing of the face.
      [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Amyl nitrite \Amyl nitrite\
   A yellowish oily volatile liquid, {C5H11NO2}, used in
   medicine as a heart stimulant and a vasodilator. The
   inhalation of its vapor instantly produces flushing of the
   face.
   [Webster 1913 Suppl.]