Saliva, breath, and blood samples were collected from 49 volunteers and over 700 values of ethanol concentration were obtained. The profiles of time-dependent changes in saliva and expired air-breath ethanol concentration were similar. The average difference between the respective values determined in blood and saliva amounted to -0.031 +/- 0.096 g/l, whereas the difference between the results for breath and saliva was -0.034 +/- 0.080 g/l. These differences in ethanol concentrations do not exceed those which occur between blood and breath (0.003 +/- 0.093 g/l). Introducing a correction value of 1.08, stemming from the varying water content in saliva and blood, results in a good agreement between the results for saliva and breath (0.005 +/- 0.077 g/l). The headspace gas chromatographic method applied for ethanol determination in saliva is specific (resolution > 1), shows good accuracy (recovery = 100.7%) and precision (SD = 0.0155 g/l). There is no matrix effect when water solutions are used for calibration instead of saliva.