Purpose Medication administration is a complex process and constitutes a substantial component of nursing practice that is closely linked to patient safety. Although intravenous fluid administration is one of the most frequently performed nursing tasks, nurses’ experiences with intravenous rate control have not been adequately studied. This study aimed to explore nurses’ experiences with infusion nursing practice to identify insights that could be used in interventions to promote safe medication administration. Patients and methods This qualitative descriptive study used focus group interviews of 20 registered nurses who frequently administered medications in tertiary hospitals in South Korea. Data were collected through five semi-structured focus group interviews, with four nurses participating in each interview. We conducted inductive and deductive content analysis based on the 11 key topics of patient safety identified by the World Health Organization. Reporting followed the consolidated criteria for reporting qualitative research (COREQ) checklist. Results Participants administered infusions in emergency rooms, general wards, and intensive care units, including patients ranging from children to older adults. Two central themes were revealed: human factors and systems. Human factors consisted of two sub-themes including individuals and team players, while systems encompassed three sub-themes including institutional policy, culture, and equipment. Conclusion This study found that nurses experienced high levels of stress when administering infusions in the correct dose and rate for patient safety. Administering and monitoring infusions were complicated because nursing processes interplay with human and system factors. Future research is needed to develop nursing interventions that include human and system factors to promote patient safety by reducing infusion-related errors.