Salivary lipids are mostly glandular in origin, but some are believed to diffuse directly from serum. This diffusion and the role of salivary lipids in oral health have scarcely been studied. Therefore, the serum and saliva cholesterol concentrations and oral health were analyzed in a group of healthy adults (n = 139; 64 men and 75 women; 34.2 +/- 5.2 yrs). Paraffin-stimulated whole saliva was collected, centrifuged (10,000 x g; 30 min, 4 degrees C), and lyophilized, and the cholesterol and other neutral lipids were extracted, separated by thin-layer chromatography, and quantified. The mean +/- SD (range) of saliva cholesterol concentration was 1.20 +/- 0.75 (0.02-5.46) mumol/L, and the saliva cholesterol level of men (1.36 +/- 0.85 mumol/L) was significantly higher than that of women (1.06 +/- 0.64 mumol/L; p < 0.05). Weak positive correlations between saliva and serum cholesterol concentrations and saliva cholesterol and serum non-high-density lipoprotein cholesterol concentrations were found (r = 0.22, p < 0.05; r = 0.28, p < 0.005, respectively). The saliva cholesterol assay detected subjects with high (> or = 6.5 mmol/L) serum cholesterol values, with sensitivity and specificity values of 100% and 29%, respectively. A positive correlation between the body mass index and the level of saliva cholesterol concentration was also found (r = 0.31 p < 0.01). Oral health, microbial counts, or saliva flow rate revealed no differences in subjects with low and high salivary cholesterol level. We conclude that, in healthy adults, saliva cholesterol concentration reflects serum concentration to some extent and can be used to select individuals with high serum cholesterol levels.