Peptidoglycan is a key structural component in bacterial cell walls, providing strength and rigidity to withstand osmotic pressure. Its presence makes it a prime target for antibiotics such as penicillins and cephalosporins, which inhibit peptidoglycan synthesis, leading to cell lysis and bacterial death. Due to its unique structure found only in bacteria, peptidoglycan is also recognized by the host immune system as a pathogen-associated molecular pattern (PAMP), triggering innate immune responses through receptors like NOD1 and NOD2. This property is exploited in vaccine adjuvants and immunostimulants to enhance immune activation. Additionally, fragments of peptidoglycan are used in research to study inflammation, host-pathogen interactions, and immune signaling pathways.