Acute dissection of the aorta is an increasingly recognised pathology, the diagnosis of which is sometimes delayed despite the fact that advances in medical imaging provide almost perfect diagnostic accuracy. Some of the symptoms are particularly suggestive. Chest pain is the key symptom, and the greater the intensity, usually described as a migratory intrathoracic tearing sensation irradiating towards the lumbar region. The other symptoms become meaningful in association with this pain: paraplegia, acute peripheral ischaemia, hemiplegia. Clinical examination is capital when a diastolic murmur of aortic regurgitation is heard or when a distal pulse is absent, the blood pressure is asymmetric or a pericardial rub is detected. The frighteningly poor initial prognosis of acute dissection of the aorta has been transformed by surgery, providing, that it is performed early. Optimal therapeutic results can only be obtained by and early diagnosis.