Antimicrobial molecules, their synthesis and use as antimicrobial treatments are described. The antimicrobial compounds are teixobactin analogues. Methods of synthesizing antimicrobial teixobactin analogues are also provided. Antibiotic therapeutics comprising antimicrobial teixobactin analogues are provided, along with methods of and formulations for treating microbial infections using such antimicrobial teixobactin analogues. Prodrugs formed using esterified forms of antimicrobial teixobactin analogues may also be provided.