Stroke is the major clinical cause of atrial fibrillation (AF). Treatments to reduce the risk of stroke and other vascular events are an important part of AF management. Oral anticoagulation is effective against stroke and has an acceptable risk of adverse events (primarily bleeding). Acetylsalicylic acid is less effective than oral anticoagulants but better tolerated. Anticoagulants are recommended for AF patients with risk factors for stroke.