In patients with an acute arterial occlusion, identification of the type of mechanism is important, because both prognosis and treatment differ for each type. The aorta is the most frequent source of arterial atheromatous emboli. Aortic arch plaques are therefore recognized as an independent risk factor for stroke, and plaques located on the thoracoabdominal aorta embolize in the visceral arteries or limb circulation. The treatment of risk factors seems the most effective preventive treatment. When atherosclerosis is patent, an anti-platelet drug such as aspirin or ticlopidine is useful. When the embolus actually occurs, heparin avoids extension of thrombus and prevents its recurrence. Surgical treatment is logical but has not been supported by any randomized trial. Cholesterol cristal embolization evolves in 3 clinical forms: 1-the paucisymptomatic form, not diagnosed during subject's lifetime and only recognized in autopsy studies; 2-a benign form such as the blue toe syndrome or cutaneous livedo, with a spontaneous mild prognosis, and 3-a diffuse multisystemic form with a very poor prognosis. More than 80% of patients with the diffuse form die. When there is renal involvement, only 25% are still alive, with renal function after 6 months of follow up. Vascular surgery is limited to patients with aneurysms, which in themselves constitute a surgical indication. For all other patients, surgery is rarely indicated because 1-the source of cholesterol cristal embolization is not certain, 2-patients are usually too weak for a major surgical intervention, and 3-the necessary aortic clamping during surgery would induce a major risk of recurrence. Prevention is the most effective treatment because in 30% of patients, embolization is due to one of the following: anticoagulant drug, recent fibrinolysis, percutaneous angioplasty, vascular surgery, diagnosis angiography and/or coronarography. The medical treatment is mostly symptomatic: rest, warm conditions, appropriate dressing, antiplatelet drugs, hydration, and organ supply when necessary, principally to ensure renal function. In diffuse and multi-visceral embolization, either colchicine or corticosteroids adjuvant therapy might be useful Prostanoid drugs are also a possible adjuvant treatment.