The effect of eugenol on oral mucous membranes.

Eugenol, in the 100 percent concentration in commercial use, was applied to a circumscribed area, 3 mm in diameter, of rat labial mucosa for 1 minute. Reaction periods of 15 minutes, 1, 2, 4 and 6 hours were then permitted. Using routine histological procedures for processing the experimental tissues, it was observed that eugenol caused denaturation of cytoplasmic proteins and loss of staining capacity of epithelium, loss of cell boundaries, swelling and cell necrosis. In addition, vesicle formation, edema in the corium, and striated muscle dissolution were observed.