  We derive low energy effective action for a short coherent conductor between
normal (N) and superconducting (S) reservoirs. We evaluate interaction
correction $\delta G$ to Andreev conductance and demonstrate a close relation
between Coulomb effects and shot noise in NS systems. In the diffusive limit
doubling of both shot noise power and charge of the carriers yields $|\delta
G|$ four times bigger than in the normal case. Our predictions can be directly
tested in future experiments.
