Chitosan is a linear polysaccharide that is biocompatible and biodegradable. Chitosan has a number of unique chemical and biological features including its cationic nature and film forming ability, mucoadhesive, antimicrobial, and wound healing properties. It is also able to bind to lipids and fatty acids and to enhance penetration through mucosal membranes. The insolubility of chitosan in aqueous solutions at pH>6.0 limits some of these potential uses, however, solubility can be improved by chemical derivatisation such as half-acetylation, methylation and glycolation. The antimicrobial properties of chitosan are well established, although the mechanism of its antimicrobial action is not fully understood. We are interested in investigating the lipid binding behaviour of chitosan and its derivatives in order to improve understanding of the polymers antimicrobial properties.