Abstract: Provided is a peptide composition for preventing or treating Alzheimer's dementia. A peptide or a salt substituent thereof according to the presently claimed subject matter exhibits effects such as suppression of LPS-mediated cytokine production, suppression of LPS-induced neuroinflammation, amelioration of cognitive impairment, suppression of beta amyloid or tau protein aggregation, and suppression of neuronal loss. The polypeptide or the salt substituent thereof can permeate the blood-brain barrier, and thus, is expected to be usefully used for preventing or treating Alzheimer's dementia.