Several studies have focused on the potential role of interleukin 1 (IL-1) in periodontitis and gingivitis. To determine the influence of a toothpaste on the concentration of IL-1b in experimental gingivitis, we performed a double blind longitudinal study using a sample with vitamin A on a test group and placebo on a control group. Twenty four young healthy volunteers participated and were randomly divided into 2 groups. The following clinical parameters were assessed: Quigley-Hein plaque index (PLI) and Saxer & Mühlemann gingival index (GI). Examinations were performed at days 18, -14, -7, -4 before baseline, and days 3, 7, 14 and 18. All oral hygiene procedures were ceased at baseline. GCF was collected from the mesiobucal site of the upper right canine using periopapers. After measuring the volume at the Periotron 8000, the samples were analyzed at our lab for the detection of IL-1b concentration by ELISA with a commercial kit (Cistron technology, USA). Our results showed a reduction in PLI and GI prior to baseline in the two groups (almost 0), both incrementing after baseline (PLI » from 0.1 to 3.0, GI » 0 to 2.0). IL-1b concentration increased from baseline to day 18 in both groups (mean: from 200 ng/ml to 510 ng/ml and from 120 ng/ml to 445 ng/ml). The local vitamin A application did not influence the inflammatory reaction. We conclude that the use of vitamin A in this form of application, doesn't markedly influence clinical signs of experimental gingivitis as measured in the concentration of IL-1b in GCF. Schlagwörter: experimental gingivitis, vitamin a, placebo, interleukin-1b, gingival crevicular fluid, Periotron 8000