Cigarette yields measured by the standard analytical procedures of the U.S. Federal Trade Commission (FTC) may not be sufficiently informative to smokers of low-yield brands because actual intake is likely to depend mainly on the aggressiveness of personal behavior. This study determined intake in smokers of 1-mg FTC tar class cigarettes, as they switched brands. Plasma cotinine levels, used as a marker of intake, spanned over a similar range of values from nondetectable to about 800 ng/ml in all brands tested. Pharmacokinetic considerations suggest that smokers of these brands--as a group--intake nicotine in excess of posted FTC values. However, mean values across smokers for each brand, as well as the brand differences in individual smokers, were closely proportional to the analytical differences of FTC nicotine yields for each brand smoked. Thus, standard analytical values may not predict absolute intake of smoke, but they appear to inform about the relative intake smokers can expect from different brands in the 1-mg FTC tar class.