Acute mesenteric vein thrombosis is an uncommon cause of intestinal ischaemia, with a considerable morbidity and mortality rate. There is a delay in diagnosis owing to the fact that patients present with non-specific abdominal symptoms; there is often a low level of suspicion by the clinician. We discuss the case histories of a 23 year-old woman and a 49 year-old woman with intestinal ischaemia caused by acute mesenteric vein thrombosis. These patients presented at two different hospital emergency departments. In patients with acute, progressive abdominal complaints, mesenteric vein thrombosis must be included in the differential diagnosis, especially if there are thromboembolic risk factors. In such patients, CT angiography (CTA) must be performed during the arterial and portal-venous phase to evaluate the mesenteric circulation.