Jiang et al. [7] and Xia et al. [53] showed that pro- biotics have a signifcant role in preventing OM caused by radiotherapy and chemotherapy by strengthening the immune system and increasing the number of T cells and lymphocytes [7, 53]. Besides the role of probiotics in oral health [54, 55] and new hopes in cancer treatments [56], probiotics strengthen the immune system by regulating the balance of microbial fora [57] and preventing the growth of pathogenic bacteria, which plays an essential role in the prevention and control of OM [26].