Chitosan is a natural, biodegradable biopolymer derived from chitin, recognized for its biocompatibility, non-toxicity, and unique properties such as antimicrobial activity and heavy metal chelation. It is widely used in water treatment for binding heavy metals and contaminants, enabling effective purification and filtration. In agriculture, it serves as a natural biopesticide, seed coating agent, and plant growth enhancer, improving disease resistance. In the medical field, chitosan is key in wound dressings, drug delivery systems, and tissue engineering due to its biocompatibility, antimicrobial properties, and promotion of regeneration. In the food industry, it acts as an edible coating to extend shelf life by reducing microbial growth and moisture loss, and as a thickener in products. Additionally, it is used in dietary supplements for fat-binding in weight loss and cholesterol control, and in cosmetics for moisturizing, anti-aging, and skin recovery benefits.