**Abstract**

Evidence is mounting to a possible link between autism spectrum disorder (ASD) and gut microbiota through the well-known gut-brain axis. Numerous mechanisms have been suggested including bacterial metabolites that could involve in chemokines, antimicrobial peptides, or neuropeptides production. Hence, numerous studies reported dysbiosis in autistic patients. Antibiotic courses are known to more or less improve neurobehavioral symptoms; however, it could lead to side effects. Modulation of the gut microbiota using pro- and/or prebiotics is therefore an appealing way of treatment. Fecal microbiota transfer is suggested to be an alternative new approach that could be promising. The aim of our chapter will be first to briefly review the current data concerning the possible role of the gut microbiota and its mechanisms in ASD and second to review the interest and limits of the pre- and probiotic supplementations in ASD treatment. Lastly, we will discuss on the potential interest of the microbiota transfer in ASD.

**Keywords:** autism spectrum disorder, gut microbiota, dysbiosis, probiotics, prebiotics, fecal microbiota transplantation
