Objectives: To enhance pharmacovigilance in Korean Medicine, this study aimed to develop and implement a standardized adverse event (AE) reporting form tailored to individualized herbal decoctions. This project sought to establish a comprehensive reporting form applicable to real-world clinical settings and to contribute to international safety standards. Methods: The development process followed a three-phase approach. First, an overview of systematic reviews was conducted to identify common AEs associated with herbal formulas, using the MedDRA System Organ Class for classification. Second, a Delphi consensus study was undertaken with 18 multidisciplinary experts over three rounds to determine the most relevant items and reactions for inclusion in the form. Finally, an applicability evaluation was conducted with nine experienced Korean Medicine doctors to assess clarity, convenience, and potential for dissemination. Based on these findings, the form was refined and finalized. Results: The finalized AE reporting form includes 58 reporting items across five domains (patient characteristics, reaction(s)/ event(s), herbal medicine information, reporter information, and overall comments) and 46 reactions. The form includes detailed information on individual herb composition, dosage, preparation methods, and causality assessment. Applicability testing confirmed its potential to improve AE reporting quality, although convenience and dissemination scores indicated room for system-level enhancement. Conclusion: This standardized reporting form provides a structured and practical tool for monitoring AEs related to decoction form of herbal medicine in Korean Medicine. Its implementation is expected to strengthen real-world pharmacovigilance, support causal inference, and serve as a foundational reference for advancing global traditional medicine pharmacovigilance systems. Future directions include iterative refinement through stakeholder feedback, expanded clinical use, and eventual proposal as an ISO international standard.