Chitosan oligosaccharides (COS), hydrolysed products of chitosan, are low-molecular weight polymers with a positive charge and good biocompatibility. COS have recently been reported to possess various biological activities, including hypoglycaemic, hypolipidaemic, antioxidantantioxidant, immune regulation, anti-inflammatory, antitumour, antibacterial, and tissue engineering activities, exhibiting extensive application prospects. Currently, the biological processes and mechanisms of COS are attractive topics of study, ranging from the genetic, molecular and protein levels. This article reviews the recent discoveries about COS, especially in metabolic regulation, immune function and tissue repair, providing important insights into their multiple biological activities, medical benefits, and therapeutic mechanisms.

壳聚糖的水解产物壳聚糖低聚糖（COS）是具有正电荷和良好生物相容性的低分子量聚合物。最近已经报道了COS具有多种生物活性，包括降血糖，降血脂，抗氧化剂，抗氧化剂，免疫调节，抗炎，抗肿瘤，抗菌和组织工程活性，具有广阔的应用前景。目前，COS的生物学过程和机制是令人关注的研究主题，涉及遗传，分子和蛋白质水平。本文回顾了有关COS的最新发现，尤其是在代谢调节，免疫功能和组织修复方面的发现，从而提供了有关其多种生物学活性，医学益处和治疗机制的重要见解。