Superwarfarin sodium exposure or poisoning is a growing public health problem. In this study patients from northern Wisconsin with superwarfarin exposure or poisoning were examined at a tertiary referral centre to determine what led to their exposure & to review the clinical manifestations, diagnosis, treatment, & prevention of superwarfarin poisoning. 11 cases were identifed including 1 adult who had attempted suicide. Full reversal of the effects of the poison was quickly achieved in the cases of accidental ingestion & attempted suicide. (38 refs.)