LL-37 Is an antimicrobial peptide which belongs to the cathelicidin family of antimicrobial peptides. LL-37, like cathelicidins, are stored in neutrophil granules as inactive precursors and are released as mature peptides when neutrophils are stimulated. LL-37 is expressed in various cells and tissues such as circulating neutrophils, bone marrow cells, epithelial cells of the skin, cells in the gastrointestinal tract and well as in the epididymis and lungs. LL-37 plays an important role in the first line of defense against infection and systemic invasion of pathogens at sites of inflammation and wound. It has shown to have antimicrobial activity against multiple Gram-Positive and Gram-negative human pathogens. LL-37 shows a broad spectrum of antimicrobial activity against bacteria, enveloped viruses, and fungi. Although it demonstrates success in helping promote wound healing but it may play a negative role in atopic dermatitis and psoriasis.