Hyperlipidaemia (HLP), characterised by an abnormally high level of serum lipids, can increase the risk of developing many diseases in the human body. HLP is prevalent all over the world and is attracting increasing attention. However, pharmacological drugs or therapies for effectively treating hyperlipidaemia are not yet available. Recent efforts have been made to seek natural anti-hyperlipidaemic compounds with fewer side effects. Chito-oligosaccharides (COS), the partially hydrolysed products of chitosan, have attracted increasing interest due to their hypolipidaemic and antioxidant effects. In this study the effects of COS on serum lipid levels, hepatic indicators and antioxidant activity were investigated in rats after 6 weeks of intragastric administration. COS can dramatically decrease total serum cholesterol, triglyceride, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, malondialdehyde and liver coefficient. COS can elevate levels of high-density lipoprotein cholesterol, the activity of lipoprotein lipase, hepatic lipase, superoxide dismutase and glutathione peroxidase. The results of this study reveal the antihyperlipidaemic and antioxidation activities of COS in hyperlipidaemic rats, suggesting its potential use as a natural hypolipidaemic drug therapy.