Enterohaemorrhagic Escherichia coli (EHEC) causes illnesses ranging from mild diarrhea to severe diseases such as haemorrhagic colitis and haemolytic uremic syndrome. Shiga toxin (Stx)-producing EHEC O157:H7 is a major EHEC serotype responsible for worldwide public health problems. Several probiotics have been known to have protective effects against EHEC O157 infection. These protective effects can be classified broadly into three categories: inhibition of O157 adherence to intestinal epithelium, inhibition of Stx production, and inhibition of O157 growth. However, the mechanisms for these protective effects against EHEC O157 infection remain barely known. We here introduce the current understanding, and propose future plans for scientific research into the protective effects of probiotics against EHEC O157:H7 infection.