Soluble (SSG, β-1, 3-D-glucan obtained from the culture filtrates of a fungus, Sclerotinia sclerotiorum IFO 9395) and particulate (zymosan) β-glucans were oxidized by sodium hypochlorite (NaClO), and the oxidized products were analyzed by gel filtration and ion-exchange chromatographies and by limulus G-test to study the metabolism of β-glucans in vivo. By oxidative degradation, SSG was gradually oxidized to anionic polymers, which decreased the molecular weight and reduced the content of the sidechain at the same time. Zymosan, a particle from fungi cell wall, was easily solubilized to a high molecular weight polysaccharide by oxidative degradation. The elution profiles on ion exchange columns and the limulus G-test reactivity of the products were similar to those of polysaccharides obtained by in vivo experiments using SSG and zymosan. These results suggest that oxidative degradation is the main metabolic pathway of β-glucans in vivo, and that the sidechains would be oxidized faster than the main chain.