In order to clarify the effect of 13 GHz microwave irradiation upon model membranes, vibrational Raman spectroscopy was performed for multilamellar dispersions of dipalmitoylphosphatidylcholine, before and after irradiation. Raman spectra of the phospholipid dispersions were recorded for the C-H ((2800 + 3100) cm-1) and the C-C ((1050 + 1150) cm-1) stretching modes, above the transition temperature T~ of the phospholipid, before and after microwave irradiation. An intensity comparison between the irradiated and nonirradiated 74 -I1 Nuovo Cimento D 1085