Enhanced reactive asymmetry for reaction upon reagent vibrational excitation has been predicted for a number of A + HB reactions. If correct, it provides a new mechanism for vibrationally enhanced reactivity. This mechanism does not necessarily require a potential energy surface with a late barrier for reaction. Rather, the required condition is a low symmetric stretch frequency at the saddle point as compared to the vibrational frequency of the reagent. The O(3P) + HCl → OH + Cl reaction can provide an experimental test of this predicted enhancement.