We implement the conditional moment closure (CMC) for simulation of chemical self-catalytic reactions in turbulent or laminar chaotic flows. Since the self-catalytic reaction is initiated by the mixing of the fresh liquid with the reacted one, we use the mean age of the fluid parcel as the conditioning variable. The proposed model is capable to describe the effect of imperfect mixing on the extinction of the reaction. (C) 2010 Elsevier Ltd. All rights reserved.