Common adverse events of herbal formulas for developing reporting forms for clinical practice and research: An overview of systematic reviews.

Background: Previous research has mainly focused on the adverse events (AEs) of individual medicinal plants rather than those of herbal formulas. This study investigated AEs associated with herbal formulas composed of two or more herbs by summarizing existing systematic reviews (SRs). We aimed to identify common AEs to develop a comprehensive reporting form for clinical practice and research, improving herbal medicine safety monitoring in South Korea. Methods: Four international (MEDLINE, EMBASE, CENTRAL, CINAHL) and three Korean databases (KISS, ScienceON, OASIS) were searched for SRs on AEs associated with herbal formulas from inception to September 13, 2024. Inclusion criteria were SRs focusing on AEs of herbal formulas composed of two or more herbs. Two researchers independently conducted the search, selection, and data extraction. Methodological and reporting quality were evaluated using A MeaSurement Tool to Assess systematic Reviews 2 and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 checklist. AEs were classified using the System Organ Class of the Medical Dictionary for Regulatory Activities. Results: Thirteen SRs were selected. The most frequently reported organ system was hepatobiliary (9 SRs), followed by nervous and gastrointestinal systems (3 SRs each). Common symptoms in primary studies were nausea ( Conclusions: Our findings provide a foundation for developing a standardized AE reporting form for herbal formulas. Further high-quality reports with specific patient conditions, herbal constituents, and causality assessments are required to enhance herbal medicine safety monitoring and understanding. Protocol registration: PROSPERO, CRD42023478440.