Abstract: ‌Currently, patients’ medication regimens are becoming increasingly complex. Complex medication regimens may affect patients' medication safety and health outcomes, so scholars have proposed the concept of medication regimen complexity, arguing that medication regimen complexity refers to multiple features of a patient's medication regimen, including the number of medications, dosage, form of the medication, time of administration, additional instructions, and relationship with food, rather than the absolute number of medications per day, and a large number of studies have been conducted. However, little is known about medication regimen complexity in China and there is a lack of research. This paper reviewed the research on medication regimen complexity to provide a reference for the research on medication regimen complexity.