Background: Diarrhea is a well-recognized side effect associated with pelvic radiation; however, there is not any effective common treatment for radiation-induced diarrhea. A popular alternative is probiotics, which have been used in several gastrointestinal disorders. Probiotics are live microbial food supplements. Furthermore, honey is a putative nutritional with a variety of health effects, including antibacterial, antioxidant, anti-inflammatory and prebiotic. The present study evaluated the effects of probiotic with or without honey on radiation-induced diarrhea. Materials and Methods: Sixty-seven adult patients with pelvic cancer underwent radiotherapy for four weeks. They randomized to receive probiotic (n = 22), probiotic plus honey (n = 21) or placebo (n = 24) from one week before radiotherapy for five weeks. Diarrhea grade and stool consistency score were recorded weekly according to the Common Toxicity Criteria system and the Bristol scales, respectively. Results: The results showed a decrease in the daily number of bowel movements (p = 0.003 and 0.006), diarrhea grade (p = 0.001 and 0.001) and the need for antidiarrheal medication (p = 0.021 and 0.041) also an increase in the stool consistency (p = 0.004 and 0.005) in patients who either used probiotic or probiotic plus honey (respectively), these were significant in weeks 4 and 5 of treatment. Conclusion: Probiotics with or without honey can reduce the incidence of radiation-induced diarrhea and the need for antidiarrheal medication