Bifidobacterium (mixed strains) has scientific evidence supporting its use in reducing certain side effects of chemotherapy, particularly gastrointestinal symptoms such as diarrhea and mucositis. Chemotherapy often disrupts the gut microbiota, leading to dysbiosis, which can worsen gastrointestinal side effects. Multiple randomized controlled trials and meta-analyses have evaluated the efficacy of probiotics—including Bifidobacterium—in this context. For example, a 2018 meta-analysis published in Supportive Care in Cancer reviewed several clinical trials and concluded that probiotic supplementation (often including Bifidobacterium species) significantly reduced the incidence and severity of chemotherapy-induced diarrhea in cancer patients. Additional studies have suggested potential benefits in improving gut barrier function and modulating immune responses, thereby possibly reducing mucositis and infections.

However, while there is a growing body of positive evidence, the results are not entirely consistent across all studies, and variations exist in probiotic strains, dosages, and patient populations studied. Some clinical guidelines cautiously endorse the use of certain probiotics, including Bifidobacterium, for managing chemotherapy-induced gastrointestinal side effects, but they also call for more standardized, large-scale research to confirm these benefits and establish optimal protocols. Overall, the current level of evidence supports a moderate recommendation for Bifidobacterium supplementation to reduce some chemotherapy side effects, particularly gastrointestinal disturbances.