In today's global market, there is a very wide range of fluoride toothpastes varying in formulation, fluoride concentration, quality control of ingredients and manufacture, and some products are transported, stored and sold to consumers in countries far removed from where they are made. The competitiveness of the toothpaste market has driven the major manufacturers to offer an increasing and frequently changing variety of formulations to support claims of caries prevention, tooth whitening, sensitivity prevention, gum health and total oral health. However, the focus of this article is to consider how variations in formulation and the fluoride content of toothpastes might affect clinical efficacy for caries prevention. On the basis of presently available evidence, it would appear that the most reliable indicator of the effective fluoride content for a toothpaste formulation is the ionic fluoride concentration (F-) as parts per million (ppm) available immediately on brushing. However, as the recent international workshop on testing methods concluded, the clinical validation, acceptance and agreement of standardised testing methods by both manufacturers and international bodies would be required. If these technical difficulties can be overcome and all manufacturers standardised on this form of expression and did not declare the total, soluble or free ionic fluoride as calculated on a theoretical basis, then it would provide a more meaningful indicator that dental professionals, pharmacies and indeed the consumer could rely upon.