Despite common skepticism of the value and reliability of Wikipedia, the collaboratively created online encyclopedia is one of the most frequently used health information resources in the world. In recognition of Wikipedia's importance, the Network of the National Library of Medicine organizes biannual editing campaigns aimed at adding citations to reputable sources of information. To date, over 300 editors have made nearly two thousand improvements to Wikipedia's health pages, and nine institutions nationwide have hosted campaign-affiliated local edit-a-thons. An established suite of technical approaches supports each campaign, and the campaigns have evolved over time to enable greater participation and impact.