Not everyone is a fan of the numerous abbreviations that have become part of the scientific language of medicine. To avoid misunderstandings regarding these abbreviations, it is wise to refer to a reliable dictionary, such as the one prepared by Heister. For instance, the abbreviation ED means effective dose to the pharmacologist, but it might also stand for emetic dose. Radiologists use the same abbreviation for erythema dose, and ED could also mean ethyl dichlorarsine. A common meaning of ECU is European currency unit, which may not frequently appear in scientific medical publications. However, ECU can also refer to environmental control unit or European Chiropractic Union. Hopefully, those making inventions and discoveries will utilize Heister's dictionary before creating new abbreviations when preparing manuscripts for scientific publications. It is a very useful resource.