This is the first known study in the United States to test the effectiveness of two verbal instructions to control the dose of toothpaste used by parents of young children. We found that parents, on average, applied significantly more toothpaste than recommended by the professional guidelines. To date, there has been only one known study, conducted in the United Kingdom, of parents' response to apply a "smear" of toothpaste. In that study, the researchers provided parents with two concentrations of fluoridated toothpaste, neither of which are commercially available in the United States. The response to the instruction to apply a smear resulted in a mean weight of 0.22 g.' Our finding was similar; the mean in response to a "smear' was 0.21 ±0.19 g, well in excess of the recommended 0.125 g of fluoridated toothpaste.