Anticoagulant therapy has been anticipated to increase risk of cerebrovascular complications (CVC) in native valve endocarditis (NVE). This study investigates the relationship between ongoing oral anticoagulant therapy and incidence of symptomatic CVC in left-sided NVE. In a prospective cohort study CVC incidence was compared between NVE patients with and without ongoing warfarin. Among 587 NVE episodes, 48 (8%) occurred in patients on warfarin. A symptomatic CVC was seen in 144 (25%) patients with only 3 on warfarin.CVC were significantly less frequent in patients on warfarin (6% vs. 26 %, OR 0.20, p=0.006).No increase in haemorrhagic lesions was detected in patients on warfarin. Staphylococcus aureus aetiology