Such patients pose therapeutic challenges because of the complex and disturbing countertransference experiences they arouse. They are likely to have suffered serious abuse themselves in the past, and there is considerable potential for this to be repeated in the treatment. This paper presents case studies that show the importance of rigorous boundary-keeping and supervision in such cases. In one case, a single mother voluntarily placed her only child into foster care because she was losing control with him, sometimes hitting him in a rage. This woman, an alcoholic, had been sexually abused by her father from age 8. In such cases, the therapist may set him/herself up as a good parent substitute, encouraging further splitting and attempted banishment of the bad object. The danger in any therapy in which the transference and countertransference are not understood and monitored, however, will be a re-enactment of the trauma and a treatment that contains sado-masochistic acting out (sometimes overtly sexual), or that becomes stuck and interminable. Close supervision in such cases, especially if the therapist is inexperienced, is essential.