Every day, people rely on prospective memory--our ability to remember to perform a future action--to carry out myriad tasks. We examined how a sham cognitive enhancing drug might improve people's performance on a prospective memory task. We gave some people (but not others) the sham drug, and asked everyone to perform a high-effort prospective memory task. People who received the sham drug performed better on the prospective memory task. They also took longer to perform their ongoing task, suggesting that they increased their effortful monitoring. These results fit with research showing that suggestions can lead people to increase cognitive effort and increase memory performance.