Pharmaceutical pollution poses an emerging environmental and public health problem. Together with increasing medicine use and pharmaceutical manufacturing effluents, improper disposal of household pharmaceutical waste significantly adds to this issue, despite pharmaceutical take-back schemes having been established in many countries. Even where take-back schemes are available return rates remain low. Previous studies have used only survey and interview methodologies and therefore merely described the situation. This study goes further, exploring not only the effects of the availability of information on pharmaceutical take-back schemes but also the effects of the framing of information provided to individuals on their intentions and reported behaviours to collect unused and/or expired household pharmaceuticals and return them to a pharmacy. The data were collected throughout three preregistered, randomised experiments with representative samples (N = 3754). The results show that tapping into individuals’ pre-existing conception of the problem and psychological biases through the delivery of environmental health, loss framing information highly increased the odds of returning household pharmaceutical waste. This result is long-lasting (Studies 2 and 3), is found in various European countries (Study 1), and remains robust in all studies. Based on the results, we suggest that, in the context of household pharmaceutical waste management, psychologically informed, proactive approaches combined with targeted local action and services can reduce the psychological and practical barriers to pro-health and pro-environmental behaviour. The findings are used to support a policy recommendation that is cost-efficient, easy to use, and effective.