Scope　Depression　is　the　leading　cause　of　disability　around　the　world;　however,　most　antidepressants　have　drug　tolerance　and　serious　side　effects.　In　this　study,　it　is　explored　whether　partially　hydrolyzed　guar　gum　(PHGG)　is　a　safe　food　that　exhibits　protection　in　a　mouse　model　of　depression.　Methods　and　Results　PHGG　is　orally　administered　to　mice　with　depression　induced　by　chronic　unpredictable　mild　stress　(CUMS)　in　two　animal　experiments　(prevention　trial　and　intervention　trial)　to　characterize　the　potentially　protective　effect　of　PHGG.　The　results　in　the　prevention　trial　show　that　PHGG　significantly　inhibits　the　loss　of　body　weight,　and　prevents　CUMS-induced　depressive-like　behavior　in　mice.　The　beneficial　effects　may　be　associated　with　PHGG　modulating　the　gut　microbiota　structure　and　then　increasing　the　levels　of　short-chain　fatty　acids　in　mice　feces　and　the　levels　of　5-hydroxytryptamine　and　dopamine　in　serum,　striatum,　and　hippocampus.　Besides,　PHGG　in　the　intervention　trial　is　less　effective　than　that　in　the　prevention　trial,　but　it　may　have　a　synergistic　effect　on　improving　depression　with　fluoxetine.　Conclusions　This　study　suggests　that　moderate　daily　intake　of　PHGG　can　contribute　to　relieving　depressive-like　behavior.