Human behaviour is complex and difficult to change. In carrying out this study, we had the goal of changing human behaviour away from using medicine made from a protected and vulnerable species. For this reason, our study investigated factors that underlie the behaviour of using bear bile in Cambodia. These factors can include personal characteristics such as age and gender; beliefs, such as using traditional medicine; or even which groups in a society are believed to be most influential (e.g. religious leaders). In our study, we investigated these factors to try to understand the behaviour of using bear bile in Cambodia. Bears are protected species in Cambodia, but face loss of habitat and illegal wildlife trade, particularly due to the use of bear bile in traditional medicines. We interviewed over 4,000 people throughout Cambodia and found that the area where people lived had an effect on the behaviour of using bear bile, but some of the other factors we expected to have an effect, such as gender, did not. Generally, we found only minor differences in behaviour and consumer characteristics across Cambodia. These insights tell us that measures to change the use of bear bile medicine, such as demand reduction campaigns, can be applied throughout Cambodia with little modification to the campaign message between areas. In addition, our finding that bear bile use is more prevalent in northeast Cambodia shows us that campaigns should begin there as a priority before expanding to the rest of the country.