Warfarin is a commonly used oral anticoagulant with a narrow therapeutic range 
and large interindividual variability in daily dose. Compared with Caucasians, 
Chinese are known to require lower doses of warfarin. Differences between 
Caucasians and Chinese in the allelic frequencies of two genes, CYP2C9 and 
VKORC1, largely explain the difference in dose requirement. There are other 
genetic polymorphisms that may further explain the response to warfarin. The 
VKORC1 genotype is an important determinant of response to warfarin in Chinese, 
but some genetic variants found in other ethnic groups that have a large effect 
on warfarin response and dosing are not commonly found in Chinese. Therefore, it 
is important to recognize and beware of ethnic differences in the 
pharmacogenetics of the response to warfarin, especially in the design of 
algorithms to aid dosing in clinical practice.