Panax ginseng roots have been used in Oriental traditional medicine for human health. Its main active components, such as saponins and polysaccharides, have been widely evaluated for treatment of diseases, but the secondary active components, such as oligosaccharides, were rarely studied. This study aimed to assess the impact of water-soluble ginseng oligosaccharides (WGOS), which are isolated from warm-water extract of Panax ginseng roots and its components were confirmed, on scopolamine-induced cognitive impairment in mice and its anti-neuroinflammatory mechanisms.