Proteolytic enzymes from neutrophils play a decisive role in tissue destruction. They release from the granulocyte during the phagocytosis or by lysis. In addition to cathepsin D, cathepsin G and collagenase, elastase is a principal component in collagenfibers destruction. Not only elastin is affected by lysis produced from elastase, but also proteoglycanes, hemoglobin, fibrinogen and collagen. In 1975 Ohlsson and Delshammer investigated in gingival biopsies the connection between elastase concentration and the granulcytes contents. In diseased tissues the mean concentration of elastase was 0,1 µg/mm3. That concentration means a proportional content of 25.000 granulocytes. Kowashi and Cimasoni (1980) reported a connection between periodontal destruction and proteolytical activity in the gingival crevicular fluid flow. Important for tissue disintegration and destructive processes is not only the enzymatical concentration, but also the activity. Kenneth et al. (1995) reported about a periodontal disease progression with an amount of over an elastolytical activity from 300 µU/µl. Elastase can appeare as a complex with the alpha-1-proteinase-inhibitor or alpha-2-macroglobulin respectively. Schlagwörter: Elastaseaktivität, Diagnostik, Mikrotest, Parodontitis