The practice of growing and harvesting plants that are genetically engineered to produce a desired pharmaceutical product. It is much cheaper than the traditional method of producing such pharmaceuticals in animal cells farmed in expensive bioreactors.
References:
1. Taylor, Marisa. Plant-Made Drugs Could Be the Future; Accessed via Internet on August 22, 2014 at: http://america.aljazeera.com/articles/2014/8/21/plant-made-pharmaceuticals.html