This paper gives an account of the psychoanalytic psychotherapy of a 23-year-old woman who sustained a dysmorphophobic reaction during and following cosmetic dental treatment. The data which emerged during the psychotherapeutic treatment is described in detail, attention being concentrated on memories, phantasies and transference reactions. A sexual theory of symptom-formation is described which provides an explanation for the patient's anomalous reaction to the dental treatment. The successful outcome of the psychotherapy is attributed to a number of factors, each of which had its own special importance.