o-Phthalaldehyde is widely used as a high-level disinfectant in the medical and healthcare industry, particularly for sterilizing medical instruments such as endoscopes. Its effectiveness against a broad spectrum of microorganisms, including bacteria, viruses, fungi, and spores, makes it a preferred choice for ensuring the safety and hygiene of sensitive equipment. Additionally, it is employed in histology and pathology labs as a fluorescent staining agent for visualizing proteins and other cellular components under a microscope. It is also utilized in analytical chemistry as a derivatizing agent for fluorescent labeling in high-performance liquid chromatography (HPLC) applications, enabling sensitive detection of primary amines, amino acids, and other compounds. Its rapid action and non-corrosive nature contribute to its suitability for these applications.