Depression is one of the most prevalent mental illnesses and is often associated withVarious other medical disorders. Since the 1980s, the primary pharmacological treatment has been Antidepressants, but due to the recent discovery of the association between the gut microbiome andMental health, probiotics have been proposed as an adjunctive or alternate treatment. The human Gut microbiome partakes in a bi directional communication pathway with the central nervous System (CNS), named the microbiota–gut–brain axis. The micro biota–gut–brain axis is believed To modulate various central processes through the vagus nerve as well as production of microbial Metabolites and immune mediators which trigger changes in neurotransmission, neuro Inflammation, and behavior. Little is understood about the utilization of microbiome manipulationTo treat disease. In this narrative review, we aim to provide a holistic perspective by synthesizing And evaluating existing evidence, discussing key biological mechanisms, exploring the history of Probiotic use, and appreciating the influence of modern diet on mental health. Five online databases Were searched for relevant studies up to December 2017. Systematic reviews that included Randomized controlled trials assessing the efficacy of probiotics in the treatment of depressive Symptoms were included.