Nature of presenting symptoms and even signs of disease can lead to a diagnosis that seems routine but is in fact erroneous because a sufficient index of suspicion is not generated in the mind of the physician dealing with the case. A young girl of about 16 years was brought to the Casualty Department, DHQ Hospital Bannu on 12 Sep 2004 with complains of severe vomiting and diarrhoea; the casualty medical officer diagnosed her as a case of acute gastroenteritis.