The chemical class of materials known as Sterilants are powerful agents specifically engineered to eliminate or inactivate all forms of microbial life on inanimate surfaces and equipment, including bacteria, fungi, viruses and bacterial spores—making them distinct from less aggressive disinfectants that may only target vegetative organisms.  They may be applied as gases, vapours, liquids or foams, and their key attributes include broad spectrum efficacy, rapid action, ability to penetrate complex surfaces or lumens, and compatibility with heat-sensitive materials when physical sterilisation (e.g., steam) is not suitable. The selection and application of a sterilant require careful attention to material compatibility, exposure time, temperature, humidity, concentration and thorough cleaning prior to use, because residues, organic load or protective biofilms can hinder performance. Common examples include ethylene oxide gas, vaporised hydrogen peroxide, ozone and peracetic acid—agents that offer sterilisation at low temperature and are widely used when conventional thermal methods are not feasible. Their deployment demands stringent safety controls, including monitoring of residuals, ventilation, operator protection and waste handling due to their inherent reactivity and potential hazard to humans, as they must reliably reach and eradicate the most resistant microbial structures such as bacterial end-spores.

Operationally, sterilants enable manufacturers, hospitals and research facilities to maintain high levels of asepsis, ensure product integrity and prevent contamination of critical surfaces or components. In pharmaceutical production lines, for example, sterilants are used to treat isolator walls, material transfer locks, aseptic filling sets and single-use systems prior to production runs. In medical device manufacturing they decontaminate components, packaging or entire rooms. Their efficacy underpins regulatory compliance, product safety and supply-chain reliability—since microbial contamination can lead to product recalls, process shutdowns and safety risks. As critical components for high-level sterilisation processes, sterilants serve as high-level microbial control agents in environments where absolute microbial reduction is essential such as pharmaceutical production, medical device manufacture, laboratory cleanrooms and critical processing equipment. As equipment and devices become more complex, with tighter tolerances, novel materials and intricate geometries, the demands placed on sterilants increase: they must demonstrate consistent penetration, residue removal, material compatibility and regulatory clearances. In addition, sustainability considerations are influencing the choice of sterilants, with increased emphasis on reduced cycle time, lower environmental impact, minimal residue, shorter aeration phases and integration into automated monitoring systems. Because of the rising complexity of manufacturing and healthcare equipment, and the increased focus on contamination control and operational uptime, sterilants remain a foundational chemical category in ensuring that highly sensitive processes achieve the required level of aseptic performance, reliability and safety.