Several bacteria that are pathogenic to animals also infect plants. Mechanistic studies have proven that some human/animal pathogenic bacteria employ a similar subset of virulence determinants to elicit disease in animals, invertebrates and plants. Therefore, the results of plant infection studies are relevant to animal pathogenesis. This discovery has resulted in the development of convenient, cost-effective, and reliable plant infection models to study the molecular basis of infection by animal pathogens. Plant infection models provide a number of advantages in the study of animal pathogenesis. Using a plant model, mutations in animal pathogenic bacteria can easily be screened for putative virulence factors, a process which if done using existing animal infection models would be time-consuming and tedious. High-throughput screening of plants also provides the potential for unravelling the mechanisms by which plants resist animal pathogenic bacteria, and provides a means to discover novel therapeutic agents such as antibiotics and anti-infective compounds. In this review, we describe the developing technique of using plants as a model system to study Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus pathogenesis, and discuss ways to use this new technology against disease warfare and other types of bioterrorism.