We calculate the shear viscosity of field theories with gravity duals of Gauss-Bonnet gravity with a non-trivial dilaton using AdS/CFT. We find that the dilaton filed has a non-trivial contribution to the ratio of shear viscosity over entropy density
and after imposing causal constraint for the boundary field theory, the new lower bound $4/25pi$, obtained from pure Gauss-Bonnet gravity, may have a small violation.
