Administration of chitosan-oligosaccharides by gastric gavage to apolipoprotein E deficient mice (apoE-/-) fed a high fat diet for 12 weeks lowered triglyceride and cholesterol levels in non-high density lipoprotein fractions, undermined atherosclerosis, increased atherosclerotic plaque stability, upregulated hepatic expression of low density lipoprotein receptor, scavenger receptor BI and also the expression of macrophage scavenger receptor BI and ATP binding cassette transporter A1. The gene discussed is APOE; the disease is atherosclerosis.