LL-37 is a 37-amino acid cationic peptide and the only known human cathelicidin antimicrobial peptide (CAMP). It is derived from the precursor protein hCAP18 and is expressed by neutrophils, macrophages, and epithelial cells at sites of infection and inflammation. LL-37 exhibits direct antimicrobial activity against a wide range of gram-positive and gram-negative bacteria, fungi, and enveloped viruses through membrane disruption mechanisms. Beyond direct killing, it is an important immunomodulator — attracting immune cells to infection sites, stimulating wound healing, and modulating inflammatory cytokine responses. It has been studied in the context of chronic wound care, respiratory infections, and innate immunity.