This review summarizes the nature of acute fluoride toxicity, its time-course, and the fluoride doses that are involved. The generally accepted "certainly lethal dose" range for 70 kg adults, i.e., from 5 to 10 g of sodium fluoride or from 32 to 64 mg fluoride/kg, is discussed. Based on recent case reports of fluoride-induced fatalities, it is concluded that this dose range has little utility in cases involving young children. The concept of a "probably toxic dose" (PTD) is advanced. The PTD, 5.0 mg F/kg, is defined as the dose of ingested fluoride that should trigger immediate therapeutic intervention and hospitalization because of the likelihood of serious toxic consequences. The concentrations and quantities of fluoride in selected dental products are discussed in relation to the PTD. It is concluded that, as these products are currently packaged, most of them contain quantities of fluoride sufficient to exceed the PTD for young children. Recommendations are made to reduce the risk of toxicity associated with their use.