The use of transgenic or virus-infected plants to produce vitally needed vaccines for developing nations has been made possible by rapid advances in plant molecular biology and biotechnology during the last decade. Plant-based vaccines would be a welcome development for many impoverished countries that lack the capital-intensive infrastructure required to produce much-needed vaccines. The approach would also be ideally suited to the delivery of oral immunocontraceptive vaccines to a wide range of herbivore species. This review looks at the progress made to date in the use of plants for vaccine production, how this technology may be used in the future to deliver immunocontraceptive vaccines to free-ranging wildlife species, and the many problems that will have to be overcome if this promising approach is to ever 'bear fruit'.