IBS-Related Faecal Incontinence: A Focused Narrative Review of Mechanisms, Evidence, and Conservative Care Considerations

Background: Faecal incontinence (FI) may occur in patients with irritable bowel syndrome (IBS), particularly when loose stool, urgency, reduced warning time, fluctuating bowel habits, or constipation with retention interferes with timely defaecation. However, IBS-related FI should be distinguished from FI caused primarily by structural sphincter injury, neurological disease, advanced frailty, or other organic gastrointestinal disorders. This focused narrative review examines IBS-specific mechanisms and conservative care considerations relevant to FI risk. Methods: This article is a focused narrative review rather than a systematic review, scoping review, clinical guideline, or formal GRADE assessment. PubMed and the Ichushi-Web/Japanese Medical Abstracts Society were searched for studies published from January 2000 to June 2026. Search terms were combined and included irritable bowel syndrome with faecal/fecal incontinence, urgency, diarrhoea/diarrhea, constipation, stool form, bowel diaries, diet, FODMAP, fibre/fiber, pelvic floor rehabilitation, biofeedback, skin care, absorbent products, ultrasound, and conservative management. Studies directly addressing IBS mechanisms or symptom management, FI assessment or conservative FI care, or implementation issues relevant to IBS-related FI were deemed eligible. Results: Direct studies of FI prevention in IBS patients are scarce. The most defensible IBS-specific targets are loose stool, urgency, reduced warning time, alternating bowel habits, constipation with retention or incomplete evacuation, diet- or medication-related triggers, stress-related exacerbation, and toilet access. Broader FI evidence supports supportive measures such as skin protection, absorbent products, pelvic floor rehabilitation, biofeedback, transanal irrigation, and referral, but these measures are not IBS-specific unless they are connected to IBS-related symptom pathways. Synthesis: Evidence was organized into three categories: direct IBS evidence, general FI evidence, and indirect implementation evidence from continence-care settings. No formal certainty ratings or recommendation strengths were assigned; statements are therefore framed as clinical considerations and areas for future study rather than guideline-level recommendations. Conclusions: IBS-related FI should be discussed as a symptom-risk pathway within IBS rather than as FI in general. Available evidence suggests the value of assessing IBS subtype, stool form, urgency, triggers, warning time, and toileting circumstances before applying general FI support. Because direct preventive trials are limited, conclusions should be interpreted as practice-informing clinical considerations rather than firm recommendations.