Irritable bowel syndrome affects one in five Australians, with abdominal pain as one of the main symptoms.Lactoferrin, found in milk, is known for its anti-inflammatory properties, and the development of a novel microencapsulated form, Inferrin, may be useful in the treatment of irritable bowel syndrome symptoms.The current study aimed to study the effectiveness of Inferrin compared to lactoferrin and a placebo on irritable bowel syndrome symptoms.Sixty-eight male and female participants over 18 years of age were recruited to complete 8 wk of supplementation with either Inferrin, lactoferrin, or a matched placebo.Outcomes were measured at baseline, week 4, and week 8.There was a decrease from baseline across all groups in IBS symptom severity at weeks 4 and 8, as well as improvements in QOL scores.Lactoferrin and Inferrin groups had a significant reduction from baseline to week 8 in weekly stool frequency.Overall, lactoferrin and Inferrin appeared to have an effect in decreasing symptoms of IBS and weekly stool frequency.