In terms of acute toxicity (i.e., the dose that can cause immediate toxic consequences), fluoride is more toxic than lead, but slightly less toxic than arsenic. This is why fluoride has long been used in rodenticides and pesticides to kill pests like rats and insects. It is also why accidents involving over-ingestion of fluoridated dental products–including fluoride gels, fluoride supplements, and fluoridated water–can cause serious poisoning incidents, including death.