Several recent studies of white coat hypertension have confirmed that it occurs in 20% or more of the hypertensive population. White coat hypertension appears to be a low-risk condition because it is associated with little or no organ damage, and is not usually associated with the metabolic abnormalities characteristic of sustained hypertension, such as high plasma lipid levels. Thus the cutoff point used to define white coat hypertension is increasingly being used as a treatment threshold. An alternative approach for defining treatment thresholds has been the study of ambulatory blood pressure in normotensive populations, taking the 95th percentile as the upper limit of normal. This approach yields unacceptably high cutoff points. Studies of the white coat effect, defined as the difference between clinic and ambulatory pressure, have shown that it is more pronounced in patients with more severe hypertension, and that it does not correlate with target organ damage. Drug treatment of white coat hypertension often results in a reduction of clinic pressure more than of ambulatory pressure, but the white coat effect is still seen in treated patients. One recently published study indicates that the prognosis of white coat hypertensive patients in benign.