益生菌是一些活的微生物，在适当摄入的情况下，可以为宿主带来健康获益。它们可以作为药物或食物补充剂被摄入，用于帮助保持人体内消化道微生物环境平衡。益生菌可以帮助维持人体自稳，增强体质，从而减少肿瘤治疗过程中产生的不良反应。目前的研究表明，益生菌可以通过激活抗凋亡通路AKT，活化COX-2途径抑制炎症反应，保护肠黏膜屏障，改善细菌移位，调节肠道微环境等机制保护和减轻放疗诱导的肠道损伤。众多临床试验虽然在采用的益生菌制剂类型、菌群种类、活菌浓度以及研究方式上各不相同，但大多数研究均发现及肯定了益生菌在预防盆腔放疗中肠道不良反应中的重要作用。随着肿瘤综合治疗手段不断进步，患者生存时间不断延长，近年来关于如何减轻治疗过程中及治疗后的不良反应，舒缓治疗带来的痛苦，改善患者治疗的体验，提高生存质量成为日益瞩目的热点，未来的研究应着眼于优化菌群配置以及在免疫力低下人群中使用的安全性等方面。

Probiotics are live microorganisms which confer a health benefit on the host when administered in adequate amounts. They can be ingested as medications or dietary supplements to help maintain a balance in the microbial environment of the digestive tract. Probiotics can help maintain homeostatic, enhance physical fitness, thereby reducing the adverse effects caused by anti-cancer treatments. Recent studies have shown that probiotics can protect and alleviate radiation-induced intestinal damage by activating anti-apoptotic pathway AKT, activating COX-2 pathway to inhibit inflammatory reaction, protecting intestinal barrier, improving bacterial translocation and regulating intestinal micro-environment. Although relevant clinical trials of probiotics varied in the type of bacteria species, the concentration of live bacteria, and research methods, most of them demonstrated that probiotics could prevent radiation induced intestinal adverse effects. With the continuous improvement of comprehensive treatment of cancer, the survival time of patients has been prolonged. In recent years, how to alleviate the adverse reactions during and after treatment, alleviate the pain caused by treatment, and improve the quality of life has become increasingly prominent. Future research should focus on optimizing the flora configuration and addressing the safety on immunocom promised patients.