Approximately 50% to 80% of patients diagnosed with abdominal or pelvic tumours experience adverse intestinal effects such as mucositis from chemotherapy and radiotherapy treatments (1,2). Inflammation or ulcers occurring as a consequence of cancer treatments can result in dosing delays and treatment reductions that can contribute to sub-optimal treatment and disease progression (2). The current evidence based literature from human, animal and laboratory studies teaches that the intestinal microbiome is intimately linked to the pharmacological effects of chemotherapy (3,4). Microbial interactions in the intestines provide the necessary cues for the development of regulated signals in part by reactive oxygen species that promote immunological tolerance, metabolic regulation and stability, and other factors, which may then help control local and extra-intestinal end-organ physiology (5). We have posited that the resident intestinal commensal cohort of micro-organisms adapt to the local environment/milieu conditions of the human host and establish a complex ecosystem in which host–microbe, milieu–microbe and microbe–microbe interactions oversee the composition and dynamics of the intestinal microbial and host cell communities (5,6). A safety, tolerability and pilot exploratory study is proposed to reduce chemotherapy induced mucositis with the administration of a standardized multi-strain probiotic formulation. The intestinal microbiota can be targeted to improve the efficacy and also reduce the toxicity of cancer treatments. Hence translational research is needed to test the hypothesis that the administration of probiotics to humans may ameliorate inflammatory conditions such as mucositis by reducing macrophage-assisted bacterial translocation (6) that is facilitated by intestinal epithelial cell dysbiosis, a gut barrier abnormality. The proposed study will also offer novel insights into the mechanism by which probiotics can beneficially shift the intestinal microbiota and influence T-cell differentiation in the mucosal environment of the intestines.