The clinical aspects, epidemiology, etiology and pathogenesis of dental erosions in man and experimental animals are reviewed. Abrasion of enamel, softened in orange juice for 3 minutes and brushed with various dentifrices, was studied with Knoop hardness measurements and scanning electron microscopy. Knoop indentations made on softened enamel surfaces were almost totally removed by 2-minute brushings with highly abrasive tooth pastes. Brushing without dentifrices only slightly changed the distinctness of the indentation outlines. Recommendations for primary and secondary prevention of erosions are given.