Pastes of different abrasives were prepared by mixing pumice, zirconium silicate (zircate), levigated alumina and insoluble metaphosphates (IMP) with water. Measurements of the amount of enamel worn off after polishing for 30 seconds with the pastes and a rotating rubber cup showed loss of a 3 or more micron thick layer from use of the zircate, pumice and levigated alumina paste and loss of less than one micron from the IMP paste. Fluoride pastes prepared by mixing the abrasives with a solution containing 4% NaF, 0.1 m phosphate and having a pH of 4.6 were tested for stability and uptake of fluoride by intact enamel. The pastes of pumice, zircate and levigated alumina increased in pH and approached neutral pH within 24 hours, while the IMP paste maintained a low pH. The uptake of fluoride from the pastes without abrasive action was pH dependent and was greatest from the IMP paste. Enamel polished with the pastes showed only a a slight gain in F. Marked deposition of F was obtained in enamel polished for 30 sec with a paste containing 0.2 m aluminum nitrate and then exposed to the fluoride solutions. The findings in the study elucidate the action of fluoride prophylaxis pastes on enamel and are in support of routine use of fluoride pastes in dental practice.