The invention relates to methods for treating and preventing radiation and/or chemotherapy related injury and/or afflictions, such as myelosuppression and decreased macrophage activity, by administering a prophylactically or therapeutically effective amount of particulate, bioavailable β(1,3 1,6) glucan. The invention also relates to methods in which β(1,3 1,6) glucan is provided in the form of whole glucan particles, microparticulate β-glucan particles or a combination thereof.
