Amongst all imaging procedures available for the exploration of an acute non traumatic abdomen, ultrasound comprises the first line technology. Non ionising, easily accessible, cheap and usable at the bedside, this imaging technique also has the advantage of close contact with the patient, which may help to focus the exploration on painful regions. Moreover, ultrasound has not only diagnostic capabilities, but also therapeutic ones. Nevertheless, sonography has limitations, which have to be known in order to avoid misdiagnosis or inadequate reassurance. The aim of this review is to present and discuss the most recent opinions about ultrasound diagnosis of acute non-traumatic abdomen related to digestive system diseases.