A 12-day-old baby boy of Pakistani-Asian ethnicity presented to the Accident and Emergency (A&E) department with a history of hematemesis. His examination and growth were normal. A number of baseline investigations--including tests for liver function, blood count, and clotting--were all normal. No bleeding was witnessed by the medical staff during an overnight stay in the hospital. Subsequently, the infant came to the hospital seven times over the next 10 weeks with reported hematemesis. Again no bleeding was found during the hospital visits. Two seizures subsequently occurred, warranting a Computerized topography scan of his brain and Electroencephalogram. Both were normal. Urine toxicology, however, found raised levels of benzodiazepines and Lamotrigine. Blood levels of Lamotrigine taken 2 days after the second seizure showed a Lamotrigine level of 35 mg/L (normal therapeutic range is 2-4 mg/L. An analysis of previously stored serum samples of the infant all revealed Lamogtrigine levels above 30 mg/L, suggesting repeated poisoning. Family members denied any knowledge of Lamotrigine or the administering of anything to the infant. A full child protection investigation was undertaken and access to the child by family and friends was denied. Six days after his second seizure, the Lamotrigine level had dropped to 2 mg/L. The investigation found that a family member was on Lamotrigine, but the family continued to deny knowledge of this fact. This case study shows a pattern of abuse that was not detected over a number of hospital visits that found no cause for reported symptoms. Urine toxicology can be helpful if no obvious cause can be found. Analysis of blood samples from previous hospital visits aided in the diagnosis. 9 references