The hormone oxytocin plays a major role in relationship formation and social functioning in animals and humans. We review theory and research examining the potential for intra-nasal oxytocin as an adjunctive medication for several mental health problems and risks: autism, schizophrenia, developmental precursors of psychopathy, social phobia, anorexia nervosa, obsessive compulsive disorder, depression (especially postnatal) and impaired maternal-infant bonding. Initial findings suggest that oxytocin administration may alleviate symptoms of autism and social phobia, but current evidence is insufficient to recommend oxytocin as a standard treatment. Despite reasonable theoretical indications, there has also been no systematic examination of oxytocin effects with psychopathy, anorexia, depression, or in mothers with problems bonding with their infants. Findings in patients with obsessive compulsive disorder suggest that oxytocin administration may not be beneficial in this group. Overall, there are good reasons to suggest that intra-nasal oxytocin may be a promising adjunctive treatment for specific mental health problems that involve impairments in engaging comfortably with other people; however, research is in its infancy; the specificity and durability of effects remain unknown, and issues of safety and modes of delivery have yet to be addressed.