Social behavior plays a pivotal role in the mental well-being of an individual. 
Continuous efforts in the past have led to advancements in the area of how the 
brain regulates emotion and cognition, while the understanding of human social 
behavior still remains eluded. A major breakthrough in understanding the 
etiology of neurological disorders is the recent insight on the role of the gut 
microbiota (GM). Human GM also referred to as the "forgotten organ" is home to 
10(13-14) microorganisms, which is 10 times the number of cells present in the 
human body. In addition, the gut microbiome (total genome of GM) is 150 times 
greater as compared to the human genome. An emerging concept gaining worldwide 
focus and acceptance is that, this much big genome can potentially control human 
behavior and other biological functions. Herein we hypothesize on the basis of 
GM's ability to modify brain and behavior and that it can directly or indirectly 
control social behavior. This review focuses on the association of GM with 
various domains of social behavior like stress, cognition and anxiety.