Vaccines against infectious disease can only be truly effective if they overcome obstacles of costs of production and storage that limit their use in parts of the world where they are truly needed. Now on page 1167, Richter et al. report progress in developing an edible hepatitis B vaccine in potatoes, taking a step toward overcoming these hurdles. Using a tuber-specific promoter to drive transcription of hepatitis B surface antigen (HBsAg), they produced potato plants that express HBsAg in their tubers. Mice fed the tubers developed a humoral antibody response, a surprising result given that HBsAg is a non-enteric pathogen. Because a limitation in edible vaccines is attaining high enough dosages, they focused on increasing the amount of antigen expressed in tubers, using alternative polyadenylation signals to enhance translation, and signal peptides to enhance endoplasmic reticulum retention (see also p. 1141 ).