During an acute outbreak of Norovirus in the local area, a 77-year-old woman was admitted with a short history of diarrhoea and vomiting. A working diagnosis of viral gastroenteritis complicated by acute renal failure, secondary to dehydration, was made. Despite judicious fluid resuscitation and regular antiemetics, the patient's symptoms persisted with only mild improvement in her renal function. An abdominal radiograph revealed evidence of significant small bowel obstruction and subsequent CT of the abdomen and pelvis identified a 1.5 cm intraluminal density at a transition point raising the suspicion of gallstone ileus. An urgent laparotomy with stone removal was carried out without complications. The patient recovered well postoperatively and was discharged home after 3 days.