High-alert medications are a leading cause of preventable patient harm worldwide, but there was no any high alert medicine list or error prevention strategy for Sri Lankan hospitals. This study addresses that gap by using interviewer administered questionnaire [n=315], five stakeholder consultative meetings [n=62] including multidisciplinary clinicians to reach consensus, followed by interviewer administered questionnaire [n=45], semi-structured three focus group discussions [n=45] to explore implementation barriers. Our findings identified [n=100] medicines as high-alert for acute care settings, and [n=40] medicines for community settings. I believe this article will be of interest and benefit to the readers of your journal. I declare that this manuscript is original, has not been published before and is not currently being considered for publication elsewhere.No conflicts of interest exist. Ethical approval was obtained from the Ethics Review Committee of Faculty of Medicine, University of Colombo (Reference number: 18-008) and approval were renewed annually as required and Ethical Review Committees of National Hospital of Sri Lanka (Reference number: AAj/ETH/COM/2017) and Colombo South Teaching Hospital (Reference number: PL/MO/2018-2019).All approval covered the full data collection period. Permission to photograph hospital pharmacies were obtained from chief pharmacist of participating hospital and no patient-identifiable information is shown.Written informed consent was obtained from all participants. The high alert medicine lists for acute and community settings are provided as S1 and S2 appendices.As corresponding author, I confirm that the manuscript has been read and approved for submission by all the named authors.