-What- Medicines are used for all types of surgeries in the operating room (OR). They are needed to provide safe and effective care. However, the use of medicines also results in waste. Research conducted by Barbariol et al. (2021) highlighted that a substantial proportion, ranging from 20% to 50%, of medications prepared in the OR ultimately remain unused and are consequently discarded. The Leiden University Medical Centre (LUMC) and ‘Nationaal Netwerk de Groene OK’ aim to minimize the waste of medicines at the OR. -Why - The environmental impact of medicines Research conducted last year by RIVM presented that the contribution of chemical products, including medicines in particular, is responsible for 41.2% of healthcare CO2 Medicine scarcity The ‘Koninklijke Nederlandse Maatschappij ter bevordering der Pharmacie’ (KNMP), presened that last year in 2022 the highest number of medicine shortage ever occurred. They predict that these kind of issues will only grow more in the further, so it is important to stay mindful about medication prescription, use and disposal. Ethical obligation Medication waste raises ethical concerns within the healthcare context. The waste of medications contradicts the principles of equity and justice, as resources that could have been allocated to patients in need are wasted. -How?- DrugWise Consequently, a final concept called ‘DrugWise’ was devised. This sustainable approach targets medicine waste prevention in the OR through a holistic approach. DrugWise consists of five critical steps: 1. Measure the waste to gain an understanding of the current situation. 2. Prioritize areas for action based on the measurements. 3. Raise awareness amongst OR staff regarding the extent and implications of medicine waste. 4. Initiate action in four key areas: medicine use, prescribing practices, stock management, and disposal. 5. Evaluate the effectiveness of the interventions implemented. The target audience of the approach is the Anaesthesia Green Team. The DrugWise approach was developed in collaboration with the primary stakeholders involved in medication use - anesthesiologists and anaesthetic nurses. This collaboration ensured that the solution was rooted in their practical experience and professional knowledge. -Future steps- Looking ahead, LUMC will serve as the pilot hospital for the DrugWise approach. Upon successful implementation and review, the intention is to broaden the reach to other hospitals, advocating for a nationwide effort in reducing medicine wastage in the OR.