Abstract: Objective To provide reference for drug marketing authorization holders (MAH) to monitor and analyze cluster adverse drug events (referred to as "cluster events"). Methods The main characteristics and causes of cluster risks/events were analyzed, introduces Monitoring methods of cluster risks, setting rules for early warning signals, key points of on-site investigation, cluster risks/event analysis were introduced. Results and Conclusion MAH can identify and judge cluster risk signals in the adverse drug reaction(ADR) database by establishing monitoring methods, to confirm and control potential drug quality risks or use risks in advance, and maximize the protection of public medication safety.

Key words: MAH, cluster events, early warning signals, monitoring, adverse drug reaction