  We study the quantum corrections to the generalized Proca theory via matter
loops. We consider two types of interactions, linear and nonlinear in the
vector field. Calculating the one-loop correction to the vector field
propagator, three- and four-point functions, we show that the non-linear
interactions are harmless, although they renormalize the theory. The linear
matter-vector field interactions introduce ghost degrees of freedom to the
generalized Proca theory. Treating the theory as an effective theory, we
calculate the energy scale up to which the theory remains healthy.
