Owner-directed aggression is reported as the most frequent of the aggression cases observed. Some factors underlying aggressive behavior are, adopting before the end of socialization period, genetic and hereditary parameters, inbreeding, environment, excessive punishment, sex, age, size, somatic reasons, territorial threats and owner dependant factors. The choices to deal with aggressive dogs is usually limited by relinquishment or euthanasia. The aim of this study is to evaluate the effects of risperidone (atypical antipsychotic) in decreasing the risk of danger in dogs presenting owner directed aggression. Sixteen household dogs from various age, sex and breed with the complaint of showing aggressive behavior were examined and after elimination of somatic reasons a scoring scale based on the considerations for assessing danger and risk of injury was prepared with the owner. Treatment was comprised of owner informing on the management and behavioral approach for each individual case and medical treatment with Risperdal oral solution 1 mg/1 mL, 100 mL sid (1 mg/m(2)). Examination, history taking and scoring were repeated after 1 month of therapy. Risperidone created satisfactory results in decreasing the risk of danger, also will prevent many household dogs from relinquishment or euthanasia.