Antimicrobial peptides (AMPs) may provide alternative treatment options against viruses and bacteria. Examination of human peptide libraries allowed the discovery of various novel peptides and proteins with anti-microbial activity. These include hemoglobin fragments, amyloidogenic peptides, α1-antitrypsin, and fragments of a mitochondrial protein. Aims of the next funding period, are the isolation, characterization and optimization of further AMPs against SARS-CoV-2 and other viruses, as well as major bacterial pathogens, including those forming biofilms. A particular focus will be the antimicrobial mechanisms of fibril-forming peptides and the generation of AMPs by immune-activated proteolytic cleavage of abundant precursor proteins.