The editors in assembling this Special Issue, "Neuro-nutraceuticals: Emerging Molecular and Functional Insights into how Natural Products Improve Brain Health", sought to advance our understanding of how such chemical entities alone or in group maintain brain metabolism and homeostasis so that neurons, glia and endothelial cells are healthy during development, ageing and in neuropathologies. The growth of interest in neuro-nutraceuticals and all aspects of their actions relevant to the health of the nervous system continues to amaze all. This Special Issue # 4 contains 39 articles, and we sought to highlight in this Special Issue important new advances and key issues pertinent to future clinical application of neuro-nutraceuticals. The diversity of topics covered is quite broad and includes significant articles on enteric microbiome and brain health. The Editors have tried to provide an up-to-date account of how nutraceuticals work at the molecular and cellular level, and what are the known molecular targets that ultimately can be leveraged clinically to enable the brain to function better. With respect to brain ailments and treatments, single molecule effects, and a therapeutic group of molecules from dietary herbals are discussed in this Special Issue.