Oscillating fields such as electrostatic or ultrasound are frequently used to induce release from nano and microcapsule carriers, but the effect of the field frequency has not been examined to date. This paper presents the results of Monte Carlo simulations for the release rate of encapsulated compounds from core–shell microcapsules subjected to an oscillating field. We find that the release rate approaches that of the permanently permeable case when the oscillation frequency is relatively high, even if the fraction of time the shell is permeable is 50% or less. Examination of the distribution of encapsulated molecules in the core shows that they rearrange during the impermeable part of the cycle, thereby enriching the shell/solution boundary and increasing the driving force for release in the next permeable part of the cycle.