Microdialysis probes of the linear design were implanted in three regions of the liver of anesthetized rats. Probes planted 1 cm apart exhibited no cross communication as demonstrated by continuously perfusing one probe with phenol for over 2 hours while monitoring the other probes for phenol and its metabolites. Regional differences in metabolic profile were observed following intravenous administration of phenol. Significantly lower concentrations of the phase two metabolites, phenol-glucuronide and hydroquinone-glutathione conjugate, were found at the probe implanted at the anterior position relative to the probes at the median and posterior positions. The kinetics of elimination were not significantly different at any of these positions. Phenol was also directly delivered to the liver through the microdialysis probes. No differences in delivery of phenol or formation of metabolites were observed at the three regions.