Studies on the mechanism of the antioxidant action of sericin are in progress in our laboratory. Because of a remarkably high (-40%) of the hydroxy amino acids (serine and threonine,table I ), the hydroxy gromups might be responsible for the antioxidant action by chelaing trace elements such as copper and iron. Current studies in our laboratory are focused on this possibility . since the content of sulfur-containing aminoacids is very low (Tabie I), it seems unlikely that the sulfhydryls of sericin are responsible for its antioxidant action.