Impairment of amyloid-b (Ab) clearance leads to Ab accumulation in the brain during the development of Alzheimer's disease (AD). Strategies that can restore or improve the clearance function hold great promise in delaying or preventing the onset ofAD.Here, we show that n-3 polyunsaturated fatty acids (PUFAs), by use of fat-1 transgenicmice andoral administrationof fishoil, significantlypromote interstitialAbclearance fromthebrainand resist Ab injury. Such beneficial effects were abolished in Aqp4-knockout mice, suggesting that the AQP4- dependent glymphatic system is actively involved in the promoting the effects of n-3 PUFAs on the clearance of extracellularAb. Imaging on clarified brain tissues clearly displayed thatn-3 PUFAsmarkedly inhibit the activation of astrocytes and protect the AQP4 polarization in the affected brain region after Ab injection. The results of the present study prove a novelmechanism by which n-3 PUFAs exert protective roles in reducingAb accumulation via mediating the glymphatic system function.-Ren, H., Luo, C., Feng, Y., Yao, X., Shi, Z., Liang, F., Kang, J. X.,Wan, J.-B., Pei, Z., Su, H. Omega-3 polyunsaturated fatty acids promote amyloid-b clearance from the brain through mediating the function of the glymphatic system. FASEB J. 31, 282-293 (2017). www.fasebj.org.