In this short paper we determine the effects of structure on the cosmological consistency relation which is valid in a perfect Friedmann Universe. We show that within \LambdaCDM the consistency relation is violated by about 1% for redshifts z\simeq 2 and this violation raises up to about 2% at z\simeq 5÷10 after which it saturates. This effect of cosmic structure on the distance redshift relation also very sensitively perturbs the determination of the dark energy equation of state via cosmic distances. It actually leads to a quite unphysical behavior of this w(z) which even diverges at z\sim3 and which we also discuss here.