The Papilla Bleeding Index (PBI) was measured on 95 interdental papillae, after which the results were compared to Sulcus Bleeding Index (SBI) scores, sulcus fluid (SF) amounts and pocket depth (PD) measurements. In 52 of the papillae, a histological evaluation of the degree of inflammation was also made, in which not only the expanse of the infiltrate but also its intensity were of interest. The PBI was positively correlated with all of the other clinical indices. Obvious and highly statistically significant correlations were demonstrated among PBI, SBI and SF. In contrast, between PBI and PD, and between SBI and PD, only weak correlations were found. The comparison of the PBI with the histological determination of inflammation revealed a clear increase in the absolute amount of inflammatory infiltrate as PBI scores increased. In addition, there was a definitive shift in the intensity of the infiltration; moderate and severe areas of infiltration became more common as PBI scores went up.