The search for economic alternatives for the production of recombinant immunoprophylactics has resulted in the concept of generating them in plants at relatively low cost. Two basic strategies are employed: the expression of recombinant antigens or antibodies in transgenic plants, or the presentation of small antigen epitopes on the surface of genetically modified plant viruses. Both approaches have resulted in the production of biologically active immunoprophylactics that have been shown in animal studies to protect from the development of disease symptoms. An especially interesting feature of producing vaccines in edible plant parts is the potential to use the transgenic plant as a vehicle for oral delivery. Substantial progress has been made over the past few years, and the first clinical trials have demonstrated the potential of this new technology. Future challenges are to express the immunoprophylactics at controlled, high concentrations in plants that could be grown locally where they are needed, and to develop easy and standardised administration procedures.