Lots of factors influencing warfarin anticoagulation effects include polymorphisms of Cytochrome P450 2C9(CYP2C9)and Vitamin K epoxide reductase complex subunit 1(VKORC1)genes, age, weight, diet and concurrent medications. Taking into consideration of physicians' work load, pharmacist-managed anticoagulation clinics were set up to help strengthen patient care in US to ensure patient medication safety. In addition, differences in genetic polymorphisms between Chinese and Caucasian have great impacts on warfarin dosage, and there is still no consensus on warfarin utilization guideline in Taiwan. Pharmacist-managed anticoagulation clinics provide individualized care, consistent monitoring and patient education. Through this service, physicians can get the latest integrated information about their patients, patients themselves are more familiar with their medication, and adherence can be improved. Therefore, those who take warfarin will get better INR control, less adverse drug-related events and treatment failure.