Isothiazolinone bactericide/Isothiazolinone-based biocides (commonly used as blends of MIT and CMI) are typically light yellow to amber transparent liquids at room temperature, with a slight odor, and are readily soluble in water and polar solvents such as alcohols and glycols. As a broad-spectrum, highly effective heterocyclic biocide and preservative, their core chemical mechanism involves disrupting microbial cell membranes and inhibiting enzyme activity to eliminate bacteria, fungi, and algae. They remain stable under acidic to neutral conditions but may degrade in the presence of strong alkalis or strong oxidizing agents, and are biodegradable. Due to their high efficacy, low dosage requirements, and relatively environmentally friendly profile, their primary application is as preservatives and antifungal agents. They are widely used in water-based coatings, adhesives, metalworking fluids, papermaking processes, water treatment, and personal care products (such as shampoos and body washes) to prevent product spoilage and microbial deterioration. It should be noted, however, that they carry potential skin sensitization risks, and their concentrations in cosmetic and personal care products are strictly regulated by laws and guidelines.