Antimicrobial　peptides　have　gradually　attracted　interest　as　promising　alternatives　to　conventional　agents　to　control　the　worldwide　health　threats　posed　by　antibiotic　resistance　and　cancer.　Crabrolin　is　a　tridecapeptide　extracted　from　the　venom　of　the　European　hornet　(Vespa　crabro).　Its　antibacterial　and　anticancer　potentials　have　been　underrated　compared　to　other　peptides　discovered　from　natural　resources.　Herein,　a　series　of　analogs　were　designed　based　on　the　template　sequence　of　crabrolin　to　study　its　structure–activity　relationship　and　enhance　the　drug’s　potential　by　changing　the　number,　type,　and　distribution　of　charged　residues.　The　cationicity-enhanced　derivatives　were　shown　to　have　improved　antibacterial　and　anticancer　activities　with　a　lower　toxicity.　Notably,　the　double-arginine-modified　product,　crabrolin-TR,　possessed　a　potent　capacity　against　Pseudomonas　aeruginosa　(minimum　inhibitory　concentration　(MIC)　=　4　μM),　which　was　around　thirty　times　stronger　than　the　parent　peptide　(MIC　=　128　μM).　Furthermore,　crabrolin-TR　showed　an　in　vivo　treatment　efficacy　in　a　Klebsiella-pneumoniae-infected　waxworm　model　and　was　non-toxic　under　its　maximum　MBC　value　(MIC　=　8　μM),　indicating　its　therapeutic　potency　and　better　selectivity.　Overall,　we　rationally　designed　functional　peptides　by　progressively　increasing　the　number　and　distribution　of　charged　residues,　demonstrating　new　insights　for　developing　therapeutic　molecules　from　natural　resources　with　enhanced　properties,　and　proposed　crabrolin-TR　as　an　appealing　antibacterial　and　anticancer　agent　candidate　for　development.