The use of fluorides in doses recommended by the International Dental Association is totally safe. Fluoride toxicity occurs only when these doses are exceeded. The human organism is capable of metabolizing fluoride when administered in low doses. Toxic doses though can cause signs and symptoms which vary from simple gastric disturbances to serious health problems or even death. The least fluoride dose which can cause signs and symptoms of fluoride poisoning is called possibly toxic dose. In the present paper the amount of 5 mgF-/kg is considered as the probably toxic dose of fluoride. In the case of accidental ingestion of a fluoride overdose the dentist should be also to calculate the amount of fluoride ingested. A simple method of calculating the amount of fluoride swallowed is presented in this paper. In addition the emergency treatment for fluoride overdoses is discussed. The danger of acute fluoride poisoning has increased lately, especially for children, due to the variety, pleasant taste smell and colour of fluoride products. Dentists should be able to estimate the toxic potential of fluoride in case of accidental poisoning and advise appropriate treatment.