  We analyze the effect of electron-electron interactions on Andreev current
and shot noise in diffusive hybrid structures composed of a normal metal
attached to a superconductor via a weakly transmitting interface. We
demonstrate that at voltages/temperatures below the Thouless energy of a normal
metal Coulomb interaction yields a reduction of both Andreev current and its
noise by a constant factor which essentially depends on the system
dimensionality. For quasi-1d structures this factor is $\sim N_{\rm Ch}^{8/g}$,
where $N_{\rm Ch}$ and $g$ are respectively the number of conducting channels
and dimensionless conductance of a normal metal. At voltages above the Thouless
energy the interaction correction to Andreev current and shot noise acquires an
additional voltage dependence which turns out to be a power-law in the quasi-1d
limit.
