There is an increasing recognition of the positive impact of trained animals, in particular dogs, in therapeutic settings. For the frail aged with cognitive impairment in high care settings, for children in hospital undergoing painful or prolonged treatments, for individuals suffering mental illness, or coping with physical or cognitive disabilities there is a growing body of experience and evidence of the value of therapy dogs. This paper gives fictitious case examples, based on the author’s experiences in hospitals and nursing homes. These, together with research outcomes of controlled interventions with therapy dogs, illustrate the comforting and calming effect on vulnerable residents and inpatients, and their impact in reducing agitation, aggression, depression and loneliness. The paper calls for further studies of this economical and effective form of therapy.