The first recombinant plant‐derived pharmaceutical protein (PDP) was human serum albumin, initially produced in 1990 in transgenic tobacco and potato plants (Sijmons et al, 1990). Fifteen years on, the first technical proteins produced in transgenic plants are on the market, and proof of concept has been established for the production of many therapeutic proteins, including antibodies, blood products, cytokines, growth factors, hormones, recombinant enzymes and human and veterinary vaccines (Twyman et al, 2005). Furthermore, several PDP products for the treatment of human diseases are approaching commercialization (Table 1), including recombinant gastric lipase for the treatment of cystic fibrosis, and antibodies for the prevention of denta...