Autism spectrum disorder (ASD) or pervasive developmental disorders are a group of developmental disorders that, compared to other socio-emotional disorders, have a clear and confirmed neurological basis, which manifests itself with impaired social interactions, deficits in communication skills, and repetitive patterns in interests and behaviors. Accordingly, recent studies show that the prevalence of this type of disorder is increasing and there is still no definitive and complete treatment. Also, the cause of this disorder is still unclear, but much evidence has been obtained about the involvement of genetic factors in the etiology of autism. Medicinal plants and their natural products are used in the treatment of various disabilities and diseases due to their high effectiveness and low side effects. In this entry, the most important medicinal plants that affect the nervous system as possible natural options for the treatment of autism are introduced.