There is a growing need to understand from the patient's perspective the experience of irritable bowel syndrome (IBS) and the factors contributing to its severity; this has been endorsed by the Food and Drug Administration (FDA). Accordingly, we conducted focus groups to address this issue. A total of 32 patients with mostly moderate to severe IBS were recruited through advertising and were allocated into three focus groups based on predominant stool pattern. The focus groups were held using standard methodology to obtain a general assessment of the symptoms experienced with IBS, its impact, and of factors associated with self-perceived severity. Patients described IBS not only as symptoms (predominantly abdominal pain) but mainly as it affects daily function, thoughts, feelings and behaviors. Common responses included uncertainty and unpredictability with loss of freedom, spontaneity and social contacts, as well as feelings of fearfulness, shame, and embarrassment. This could lead to behavioral responses including avoidance of activities and many adaptations in routine in an effort for patients to gain control. A predominant theme was a sense of stigma experienced because of a lack of understanding by family, friends and physicians of the effects of IBS on the individual, or the legitimacy of the individual's emotions and adaptation behaviors experienced. This was a barrier to normal functioning that could be ameliorated through identifying with others who could understand this situation. Severity was linked to health-related quality of life (HRQOL) and was influenced by the intensity of abdominal pain and other symptoms, interference with and restrictions relating to eating, work, and social activities, and of the unpredictability of the condition. This study confirms the heterogeneous and multi-component nature of IBS. These qualitative data can be used in developing health status and severity instruments for larger-scale studies.