The distinction between food and medicine may be reduced by producing human pharmaceuticals in food crops. The benefits of such an approach are abundantly clear. Producing biopharmaceutical molecules synthetically, or purifying them from microbial fermentation systems, can be extremely difficult and expensive. Plants, on the other hand, especially food crops such as corn, are extremely efficient producers of large amounts of protein. This ability could be extremely important for the production of oral vaccines, for example, where large doses are typically required to elicit immunity.