RATIONALE: Patients with radiation-induced enteropathy (RE) after cancer treatment show similar symptoms as patients with irritable bowel syndrome (IBS). The low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (LFD) is a widespread management strategy for IBS. We aimed to investigate if there may be a positive effect of LFD on symptoms and health-related quality of life (HRQOL) in patients with RE. METHODS: In an open non-controlled pilot study, 11 patients (all female) with RE-related IBS symptoms were recruited largely based on own initiative. All followed LFD for four weeks. IBS Severity Scoring System (IBS-SSS) and IBS Symptom Questionnaire (IBS-SQ) were used to assess symptoms. Short Form Nepean Dyspepsia Index (SF-NDI) and 12-item Short Form Health Survey (SF-12) evaluated HRQOL. A three day food record was used to estimate baseline intake of FODMAPs and to reveal dietary changes. RESULTS: FODMAP intake was successfully reduced, although LFD was found a burdensome intervention. IBS symptoms improved significantly based on mean total score of IBS-SSS and IBS-SQ, which changed from 310.2 ± 60.7 to 171.4 ± 107.2 (p = .001) and 27.4 ± 4.1 to 15.7 ± 10.1 (p = .002). HRQOL improved based on SF-NDI total score (30.5 ± 9.4 to 18.3 ± 8.2, p = .001) and based on mental (p = .047) and physical (p = .134) score of SF-12. Main additional dietary changes were reduced intake of energy, carbohydrates, and fiber. CONCLUSION: Our findings from this small-scaled pilot study indicate that the LFD may alleviate symptoms and improve HRQOL in patients with RE. Further controlled studies with larger sample size should be conducted to verify our results and hopefully enable implementation of LFD as a future part of the management strategy for RE.