The prescription of a medicine (pharmaceutical) is the most common healthcare intervention to diagnose, prevent, treat or cure disease. NHS Scotland spends over £2 billion per year on medicines, and prescribing rates have risen by >40% in the past 15 years. Rising medicine use leads to an increasing number and complexity of biologically active pharmaceutical compounds entering public wastewater and the environment – and pharmaceutical pollution is now a globally recognised public health and environmental issue. This proof-of-concept project investigated the feasibility of environmentally-directed prescribing through development of a framework with environmental impact data of pharmaceuticals in the Scottish water environment for inclusion in healthcare decision-making. Researchers utilised a transdisciplinary, mixed-methods approach combining environmental science, computational modelling, prescribing, and qualitative health services methods and data. Objectives included: 1) selection of pharmaceuticals and framework criteria through Nominal Group Technique (NGT) consensus methods considering environmental and clinical perspectives; 2) application of Bayesian Network modelling to create the framework with environmental impact (hazard and risk) data; 3) identification of prescriber and public perceptions of eco-directed prescribing through focus groups.