Aims. Frequent users of the emergency department (FUED; five ED visits or more per year) often have negative experiences in health care settings, potentially aggravating their health problems. Scarce research has explored FUED experiences in health care in Europe, none in Switzerland. Thus, this study aimed to conduct an in-depth exploration of FUED experiences in health care settings in Switzerland. Methods. Semi-structured interviews were conducted among 20 FUED (75% female; mean age = 40.6, SD = 12.8). Qualitative data were subject to inductive content analysis. Results. Five main themes emerged from the analysis. The main findings documented that FUED experiences in health care were mostly negative, leading to negative emotions, dissatisfaction and a loss of confidence in the system, although some positive experiences were reported as well. The relationship with health care workers was perceived as playing a key role in FUED experiences. Conclusion. The findings indicate that FUED often have negative experiences in the health care system in Switzerland. The relationship with the health care staff is reported as a decisive ingredient of the experience in health care. Future research is needed to develop awareness-raising interventions for health care staff to improve FUED experiences in health care.