To find out a novel source for natural antioxidant ‘chitosan’, from the shell of donacid clam Donax scortum which was characterised by UV-Vis spectroscopy, FT-IR spectroscopy, Potentiometric titration, Viscometry and DSC. Chitosan was evaluated for antioxidant efficacy through various
antioxidant assays such as conjugated-diene method, DPPH radical scavenging assay, reducing power and metal ion chelating assay. This study has not only brought out the importance of shell for its utilization into a potential source for obtaining another natural antioxidant that may again form the basis for the source of active principle of a drug or the drug itself in future.