Recent in vitro findings indicate that cytokines represent an important pathway of connective tissue destruction in human periodontitis. The biological effects of interleukin‐1β (IL‐1β) and interleukin‐8 (IL‐8) are relevant in this regard, and the objective of this study was to compare the levels of these molecules in gingival crevicular fluids (GCF) from patients with adult periodontitis (experimental group) and from individuals with clinically healthy gingiva (control group). GCF was collected for 30 seconds using a periopaper strip and the volume of the sample determined. Following elution of the fluid, assays for IL‐1β and IL‐8 were carried out by ELISA. The concentrations (ng/ml) of cytokines were calculated in the original volume of GCF on each strip. The total amounts (pg/site) of cytokines were expressed as the concentrations multiplied by volumes of GCF. The total amounts of IL‐1β and IL‐8 of the experimental group were significantly higher than the control group. The total amounts of both cytokines were markedly reduced following phase 1 periodontal treatment. The clinical parameters were positively related to the total amounts of IL‐1β and IL‐8. IL‐1β concentrations and total amounts were also positively related to IL‐8 suggesting that the GCF IL‐8 levels are influenced by local IL‐1β activities. These data indicate that the total amounts of IL‐1β and IL‐8 exhibited dynamic changes upon severity of periodontal disease. The levels of IL‐1β and IL‐8 in GCF are valuable in detecting the inflammation of periodontal tissue. J Periodontol 1995;66:852–859.