Raman spectroscopy was applied to the analysis of structural changes in lyophilised sodium hyaluronate after proton and γ irradiation (0.5, 5, 50, 100, 200 and 600 Gy). Characteristic Raman bands of the polysaccharide were sensitive to irradiation. Significant damage was observed at doses of 50 Gy or higher. The spectral changes confirmed radiation-induced loss of native solution conformation, destruction of primary structure, fragmentation, cross-linking and elimination of functional groups. Differences in the effects of proton and γ radiation on sodium hyaluronate are discussed. Copyright © 2010 John Wiley & Sons, Ltd.