Plasma fluoride (F) concentration and urinary F excretion were studied in 5 children, age 3–4 years, after intake of F tablets (0.5 mg) and 0.6 g of two NaF toothpastes containing 0.1 and 0.025% F – corresponding to 0.6 and 0.15 mg F, respectively. Mean baseline plasma F was 0.79 ± (SD) 0.10 μM. After intake of tablets or 0.1% F toothpaste the increase in plasma levels was almost identical in all children. The plasma peaks were registered at 30 min and were 4.47 ± 0.47 and 3.63 ± 0.45 μM F, respectively. The 0.025% F toothpaste only resulted in a modest increase: 1.5 ± 0.19 μM F. The F urinary output showed great interindividual variations which demonstrated the difficulties in obtaining reliable information on F intake from this parameter alone.