The oropharyngeal delivery of interferons: where are we and where do we need to go?

The controversial concept of oral delivery of interferon (IFN) is reviewed in relation to possible mechanisms of action. Although there is a rational basis and some positive clinical results for believing that it may work, problems remain to understand which is the most effective IFN preparation and why. Owing to a minimal cost and lack of toxicity, the oral as well as other unconventional routes of IFN delivery deserve to be evaluated because they may become useful.