In this letter to the editor, the author describes the case of a 45-year-old lab technician who repeatedly injected herself with hazardous biomaterials. She had a long psychiatric history marked by repeated suicide attempts, impulsive & violent acts & dissociative episodes, all compatible with borderline personality disorder. During a 1-year period, the subject injected herself some 20 times with HIV-infected blood. She reported that self-injection produced a soothing sense of emotional relief.