The ambiguous terminology 'Iodine Prophylaxis' used for decades to provide 
iodine to the population for very different purposes as well as its replacement 
with 'Iodine Thyroid Blocking' is discussed and argued. Recommendations of 
international organisations regarding the action level for Iodine Thyroid 
Blocking and their implementation in national regulations in a few Member States 
of the European Union, and particularly in Hungary, is presented and discussed.