Deep mycoses have been clearly demonstrated to release beta-glucans into the blood. Structure of the beta-glucan was, at least in part, suggested to be a mannoprotein beta-glucan complex (CAWS) as assessed by biochemical and immunochemical analyses of the extracellular macromolecular fraction of Candida albicans. Half clearance time of i.v. administered CAWS was about 30 min in mice. In addition to the reactivity with limulus G-test, CAWS was found to exhibit various biological activities, such as cytokine synthesis by leukocyte, platelet aggregation, lethal toxicity, enhancement of side effect of indomethacin, induction of coronary arteritis in mice, and so on. In this review, the chemical properties and biological activities of CAWS are discussed.