formalin

Formalin is an aqueous solution of formaldehyde, typically containing about 37% (by weight) of formaldehyde gas dissolved in water and stabilized with 10–15% methanol to prevent polymerization[1][9]. It is a clear, colorless liquid with a strong pungent odor. Formalin acts as a potent fixative and preservative due to its ability to cross-link proteins and nucleic acids. Its primary mechanism of action is the denaturation and cross-linking of biological macromolecules, which preserves tissue structure for histological examination or long-term storage[1][6]. In medicine, it is widely used for tissue fixation in pathology labs, preservation of biological specimens (anatomy/museum samples), sterilization/disinfection (including medical equipment), vaccine production (virus/bacterial toxin inactivation), and occasionally as a topical agent for refractory hemorrhagic proctitis[6][8][10]. Formalin’s antimicrobial properties make it effective against bacteria, fungi, viruses, and parasites. However, it poses significant health hazards including irritation to skin/eyes/respiratory tract and carcinogenicity upon chronic exposure.

Other names

formaldehyde solution37% formaldehyde solutionaqueous formaldehydemethanal solution