This paper describes the treatment of thirty-three patients who were suffering with obsessional symptoms and who were given the drug clomipramine (Anafranil, Geigy Pharmaceuticals). The symptoms were classified into phobic ruminations, non-phobic ruminations and rituals as well as into the less familiar group of normal and bizarre obsessions. Progress was assessed using the Shapiro card method and a brief description of this method is given. The results show that clomipramine possesses a specific anti-obsessional quality and that the use of this preparation is an effective treatment for obsessional patients. The paper also discusses certain aspects of therapy as well as suggesting an aetiological basis of obsessional symptoms.