With the advent of antibiotic resistance, it is crucial to find substitutes to conventional antibiotics. Host defense peptides (HDPs) are considered to be viable alternatives, because they are broad spectrum and bacteria develop little or no resistance towards HDPs. Interestingly, only few HDPs are used as therapeutics, due to problems such as host toxicity, protease cleavage and short half-life. Our group investigates the mechanism of action of these HDPs to find ways to improve them, as well as novel delivery tools (e.g. polymer conjugation).