Spontaneous mesenteric haematomas are rare. They have been reported to be associated with coagulopathies, connective tissue disorders, past trauma, arteriopathy and pancreatitis. However, some cases have been reported in which there is no apparent underlying aetiology. Here we report such a case and we review the literature that discusses optimal diagnosis and management. In this case, spontaneous haemostasis occurred by intra-abdominal tamponade and the regression of the haematoma was monitored with regular imaging.