An electrochemical fuel cell is operated with periodic reactant starvation at either or both electrodes. Periodic reactant starvation conditions cause a change in the potential of the starved electrode and may result in the removal of electrocatalyst poisons and in improved fuel cell performance. This technique may have other beneficial effects at the electrodes, including performance improvements due to water management effects or localized heating effects at the starved electrode. In a preferred method, while successive localized portions of a fuel cell electrode are periodically reactant starved, the remainder of the fuel cell electrode remains electrochemically active and saturated with reactant such that the fuel cell is able to continue to generate power.