A detailed stochastic analysis of the Brusselator scheme has been performed to bring out the effect of external noise on the system. The diffusion parameter [formula presented] was taken to be fluctuated by external noise and a complete solution diagram with the composition variables X and Y has been generated. These noise-induced transitions reveal that this system attains a stable state not described by its deterministic analysis. The stochastic analyses also reveal that the structural stability of such systems is disturbed even for a slight external perturbation in the bifurcation parameter, and in a certain range of noise intensity (σ) and correlation time (τ) some different spatial and temporal structures arise. © 1997 The American Physical Society.