Background: Lean healthcare methodology has been applied in healthcare institutions to process management and waste reduction, focusing on reviewing processes based on three organizational principles: patient, time and value. The current research sought to explore optimization opportunities in the management of pharmaceutical stocks in a Brazilian public hospital through the utilisation of a lean healthcare approach. Methodology: Firstly, the sector as well as the dynamics that compose the processes within the organization were studied, which led to the elaboration of a set of value flow mappings to identify the main sources of system waste and the respective improvements demanded. Once the main sources of waste were identified, a multi-criteria decision model was developed to prioritize action plans for their elimination or reduction. Results: As a result, improvements were proposed to address the main system needs, directing the organization towards a more assertive and efficient optimization process. The multi-criteria model supported the decision maker with the ordering of action plans to be implemented according to the sector conditions and needs. The action of setting specific units for the sourcing of each type of supply was classified as a priority, as the value stream map (VSM) carried out identified several units supplying the same stock items, bringing inconsistency in the stock value. Conclusion: It was possible to detect the singularities involved in the processes of lean approach implementations in hospital systems, displaying its optimization potential for complex systems, at the same time that it presents alternatives to eliminate waste and reduce supply disruptions and storage costs. Ethic statement: Not applicable