We have analyzed the build-up of the Stokes field when the Raman active medium is coupled to a laser field undergoing amplitude fluctuations. By means of the theory of multiplicative stochastic processes, we have obtained a rigorous solution for Gaussian fluctuations and have shown that fluctuations enhance the build-up of the Stokes field. Such an enhancement is not a universal occurrence in nonlinear optical processes. There are cases where optical processes are retarded by chaotic fluctuations. We have derived a general rule by means of which we can determine whether enhancement or retardation occurs in a particular situation.