Beta-(1,3)/(1,6) D-glucan, a component of the fungal cell wall, has been shown to stimulate the immune system, enhance hematopoiesis, amplify killing of opsonized tumor cells and increase neutrophil chemotaxis and adhesion. In view of these attributes, the beta-glucans should be studied for both their therapeutic efficacy in patients with cancer as well as an adjunctive therapy in patients receiving chemotherapy as a maneuver to limit suppression of hematopoiesis.In this study, twenty patients with advanced malignancies receiving chemotherapy were given a beta-(1,3)/(1,6) D-glucan preparation (MacroForce plus IP6, ImmuDyne, Inc.) and monitored for tolerability and effect on hematopoiesis. Our results lead us to conclude that beta-glucan is well-tolerated in cancer patients receiving chemotherapy, may have a beneficial effect on hematopoiesis in these patients and should be studied further, especially in patients with chronic lymphocytic leukemia and lymphoma.