Self-derivation of new factual knowledge is crucial for building a knowledge base. In three experiments, we investigated self-derivation about prescription medications. In Experiment 1, adults self-derived new knowledge across textual materials on 40% of trials. Participants in Experiment 2 performed similarly (42%), even when half the information was presented in videos. It was crucial that participants received both learning episodes to successfully self-derive: control condition participants received half the necessary information and performed significantly lower. When a delay was imposed between related facts in Experiment 3, participants self-derived on only 33% of trials and performance did not differ from the control condition. The present research expanded our understanding of adults' learning and self-derivation across media about medications. It revealed room for improvement in adults' learning and self-derivation about health information. This work suggests the need to identify factors that alter performance, including better understanding of the properties of information sources.