In most of globular clusters, surface abundance anomalies are observed not only from red giant stars but also from main sequence stars. We discuss the possibility that the latter anomalies can be explained in terms the pollution due to mass transfer during close encounters with red giants, the latter of which have already developed the anomalies through their internal processes. If this is the case, the main sequence stars with the abundance anomalies may serve as a probe into the star-star interactions in dense cores of globular clusters.