Résumé: Our analysis assessed the impact of information on patients' preferences in prescription vs over-the-counter (OTC) delivery systems. A contingent valuation (CV) study was implemented, randomly assigning 1594 people into the receipt of limited or extended information concerning new influenza drugs. In each information arm, people answered two questions: the first asked about willingness to pay (WTP) for the new prescription drug; the second asked about WTP for the same drug sold OTC. We show that WTP is higher for the OTC scenario and that the level of information plays a significant role in the valuation of the OTC scenario, with more information increasing the WTP. In contrast, the level of information has no impact on WTP for prescription medicine. Thus, for the kind of drug (i.e. safe, not requiring medical supervision) considered here, a switch to OTC status can be expected to be all the more beneficial as the patient is provided with more information concerning the capability of the drug. Conclusions: Our results shed some light on one of the most challenging issues that health policy makers are currently faced with, namely the threat of a bird flu pandemic. Drug delivery is a critical component of pandemic influenza preparedness. Furthermore, the congruence of our results with the agency and demand theories provides an important test of the validity of using WTP based on CV methods. [Authors]