Recently,reportedthat crude chitin from crab shells did not show any antimicrobialactivity but chitin from shiitake stipes and mushroom exhibited abetter inhibitory effect on bacterial growth than chitin from crabshells. After purification, chitosan from shiitake stipes and crabshells exhibited excellent antimicrobial activities against speciesof pathogenic bacteria. However, chitosan from shiitake stipes wasslightly more effective than that from crab shells. It was demon-strated by Byun et al.