The invention concerns agents with anti-bacterial activity and methods and intermediates for their production. The present invention further concerns the use of such agents for the treatment of bacterial infections in animals, including man. The agents are derivatives of vancomycin-type antibiotics, of structure: V-L-W-X; wherein V is a glycopeptide moiety which inhibits peptidoglycan biosynthesis in bacteria; L is a linking group; W is a peptidic membrane-associating element such as an element based on naturally-occurring animal or bacterial peptide antibiotics; and X is hydrogen or a membrane-insertive element.