Fixatives for electron microscopy are specially designed solutions that aim to preserve minute cellular structures and make them visible for examination under the electron microscope. These fixatives must be highly reactive and fast penetrating to ensure effective stabilization of biological samples, and they should not produce artifacts in the electron microscopic image to allow accurate and unbiased analysis of the structures. The use of these fixatives is particularly important in specialized laboratory applications to obtain reliable and reproducible results in electron microscopy. In this context, careful selection and handling of the fixatives is crucial for the success of the investigation.