Context • Crohn's disease and ulcerative colitis result in similar gastrointestinal (GI) symptoms, including pain, diarrhea, stools with mucus or blood, and ulceration or tissue damage within the alimentary canal. Gut microbiota play a crucial role in triggering, maintaining, and exacerbating inflammatory bowel disease (IBD). Probiotics might help to rebalance the gut flora in a positive way, shifting from pro- to anti-inflammatory. Objectives • The study intended to investigate the safety and use of probiotics and the biological effects of probiotic bacteria on IBD. Design • The research team performed a literature review. The team conducted a database search in April 2015 using Google Scholar and PubMed to find studies relevant to probiotics and their use in IBD. Only papers that were published in English were considered, and all available years in each database were searched. The initial search identified 38 published articles, for which the research team obtained full texts and independently read them in full to identify those papers suitable for inclusion in the review. Setting • The study took place in the main library of the University of Lahore (Islamabad, Pakistan). Results • Many strains of probiotics exist, but the most common strains available today are (1) the Bifidobacterium species, (2) Enterococcus faecium, (4) the Lactobacillus strains, (4) Saccharomyces boulardii, (5) the Bacillus species, and (6) Pediococcus, all used to produce beneficial health effects. These species showed their beneficial effects on the host using different mechanisms involving (1) production of proteins, quorum sensing signaling inhibitors, butyrate, immunoglobulin A, and short-chain fatty acids; (2) decreased production of tumor necrosis factor alpha and interleukin 8; (3) increased expression of mucin 2; and (4) increased upregulation of defensin. Conclusions • Studies on probiotics in animal models of IBD are promising, and clinical results in IBD patients are encouraging; however, the data are limited, and few studies are placebo controlled. Additional placebo-controlled, double-blind studies in IBD are required before recommendations can be offered for routine use of probiotics in IBD. Additional organisms may eventually be developed through genetic engineering. The current evidence also indicates that probiotic effects are strain specific; they do not act through the same mechanisms nor are all probiotics indicated for the same health conditions. More research is needed to determine what strains and at what dose probiotics become more useful as part of a clinical intervention.