The systemic fluoride absorption following topical fluoride gel application has been monitored in two groups of 6 healthy volunteers. Plasma F- levels and urinary fluoride excretion were measured after the use of a 1% and of a 2% gel preparation (commercial products). The resorption of these gels seems lower than reported previously for other preparations. Creatinine clearance remained unaffected after a single application of the gels in healthy subjects.