Structure and functions of cell membrane are susceptible to alterations as a consequence of interactions with chemical species. The objective of the proposed experiment is to study the effect of addition of salicylate drugs and amyloid beta (ABeta) peptide on the dynamics of phospholipid based uni-lamellar vesicles using quasi-elastic neutron scattering study. ABeta peptide plays a critical role in proliferation of Alzheimer¿s disease and salicylate drugs are the main ingredients in aspirin that is used widely in medications as an analgesic to relieve pain and reduce fever. This user proposal will help us to understand the interaction of these additives with lipid bilayer and its correlation with the microstructure of the vesicles.