Catecholamines are important elements of neuroendocrine regulation, and their concentrations in dental pulp are of interest. Two groups of teeth were used in this study: (i) healthy teeth and (ii) periodontally diseased teeth. After the processing of dental pulp obtained from the extracted teeth, the samples were analyzed in a computer-controlled Merck-Hitachi HPLC system at 280 nm wavelength. The external and internal standard methods of the HPLC Manager Program were used for validation. In healthy teeth the norepinephrine level of dental pulp was 4.86 +/- 0.96 micrograms/g, whereas the epinephrine level was 8.1 +/- 1.18 micrograms/g. In periodontally diseased teeth norepinephrine and epinephrine levels were significantly higher (p < 0.01) at 13.98 +/- 21.13 micrograms/g and 1.42 +/- 0.32 micrograms/g, respectively. Dopamine could not be demonstrated in 87% of the pulps. Summing up we succeeded in demonstrating norepinephrine and epinephrine in human pulp, but in most cases we could not demonstrate dopamine. Further investigations are needed on pulp tissue infected because of caries.