This account of the inpatient psychoanalytic psychotherapy of a mother and child at the Cassel Hospital, London is of a serious case of so-called ‘Munchausen's syndrome by proxy’. The mother presented two of her children to medical staff with complaints which were later found to be due to her chronic poisoning of them, by salt administration, which narrowly missed causing their death. It is an account of a treatment using both individual and group analytic methods in a psychoanalytic therapeutic community. Attention is drawn to the mother's use of projective identification defensively and malignantly in a concrete fashion and its gradual conversion into a more benign agent. The function of the institution as a container is described, and comment is made on the experience of working with severe cases of child abuse.