Drug products are identified and reported using a unique, three-segment number, called the National Drug Code (NDC), which is a universal product identifier for human drugs.  FDA inputs the full NDC number and the information submitted as part of the listing process into a database known as the Drug Registration and Listing System (DRLS), which is transforming into the electronic system (eDRLS). Several times a year, the FDA extracts some of the information from the DRLS data base (currently, properly listed marketed prescription drug products and insulin) and publishes that information in the NDC Directory.