Warfarin or not warfarin? That is the question.Each day, physicians who treat elderly patients, especially octogenar-ians, consider this dilemma. Benefits of warfarin are well known inpatients 75 years of age or older. However, compared with youngerpatients, this group is at higher risk for intracranial hemorrhage andother types of warfarin-associated bleeding. Fang and colleagues (1)examined the risk for intracranial hemorrhage according to age andinternational normalized ratio (INR). However, the patients theyexamined were not good candidates for warfarin therapy. For manyreasons, it is more difficult to control INR in patients 85 years of ageor older. A high percentage of these patients have gait disturbances,neurodegenerative diseases, and other prevalent diseases (for exam-ple, diabetes, chronic obstructive pulmonary disease, and heart fail-ure). Many take drugs such as amiodarone, antibiotics, corticoids,statins, omeprazole, and nonsteroidal anti-inflammatory drugs,which can increase the effect of warfarin. Other patients have socialproblems that make accurate INR monitoring difficult. Because wetreat patients, not percentages or relative risks, we should avoid gen-eralizing recommendations about oral anticoagulation in very oldpatients. We should tailor prescription of anticoagulants accordingto each patient’s associated diseases, concurrent medications, andfunctional and mental status.