Purpose The purpose of this paper is to introduce eye tracking as a method for capturing direct and indirect measures of online human information search behaviour. The unique contribution of eye-tracking data in studying information behaviour is examined in the context of health information research. Design/methodology/approach The need for multiple methods of data collection when examining human online health information behaviour is described and summarised. The nature of human eye movements in information use and reading is outlined and the emergence and application of contemporary eye-tracking technology are explained. Findings The paper summarises key contributions and insights that eye tracking has provided across multiple studies, with examples of both direct data on fixations and gaze durations as well as theoretical assessments of relevance and knowledge gain. Originality/value The paper provides a basic introduction to the application of a unique method for information research in general and online health information search in particular and provides readers with an awareness of how such data are captured and interpreted.