The cultivation of plants with specific properties has been the foundation of medicine for milennia. Modern biotechnology may one day extend their medicinal uses to include the delivery of vaccines. Edible vaccines that are heat stable, easy to administer and cheap to produce have the potential to redress many of the production, distribution and delivery limitations faced by traditional vaccines. Published data have shown that the concept of an edible vaccine is valid. Transition from a model system into a practical reality still has some way to go, including managing issues of oral tolerance, genetically modified organism safety, and effective vaccine doses. Successful edible vaccines have the potential to transform health policy and practice in both developed and developing countries.