In this issue, Kramer and colleagues show that transgenic maize expressing the egg white protein avidin is highly resistant toward many species of stored-product insect pests. This toxicity is mediated by avidin's ability to tightly bind to and sequester the essential coenzyme biotin, causing stunted growth and mortality in the insects. In anticipation of the potential use of transgenic avidin plants in food or feed production, Kramer et al. fed it to mice as their sole diet for three weeks but observed no ill effects (see p. 670).