Internet information undergoes no quality controls and virtually anybody can publish anything. Because of this, it is difficult for searchers to take information retrieved from the Internet at face value. A related problem is the uncontrolled promotion of medical products on the Internet. A further problem of today's Internet is that authors use no uniform keywords and other descriptive labels, which deteriorates the quality of search results. A solution for all these problems could be widespread use of descriptive and evaluative metainformation associated with medical Internet information. Our concept is based on a recently established infrastructure for assigning metadata to Internet information, the so-called PICS Standard (Platform for Internet Content Selection). We prototyped a PICS-based rating vocabulary for medical information (med-PICS), containing descriptive and evaluative categories, to be used by the webauthor and third-party label services (such as medical associations), respectively. We propose an international effort to assign metadata to medical Internet information.