The present invention provides a reduced fat probiotic strain, composition thereof and use thereof. The probiotic strain is Lactobacillus plantarum TCI378 (BCRC910760), which itself and its metabolites can inhibit the accumulation of fat in fat cells, and can effectively reduce the amount of fat in cells so as to achieve the goal of reducing fat and obesity. Wherein the Lactobacillus plantarum TCI378 metabolites of the present invention contains an effective component of Pyroglutamyl- tryptophan, 1-Methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, and/or 3-Phenyllactic acid.本發明提供一種減脂之益生菌株及其組合物與用途,該益生菌係為植物乳桿菌TCI378(BCRC910760),其本身以及其代謝產物具有抑制脂肪細胞中脂肪的堆積,而能夠有效減少細胞中脂肪的含量,達到減少脂肪與肥胖的目標。其中本發明之植物乳桿菌TCI378的代謝產物具有色胺酸基焦麩醯胺、1-甲基-1,2,3,4-四氫-β-咔啉-3-羧酸、及/或3-苯乳酸之效性成分。