Inclusion Criteria:  Participant has diagnosis of chronic constipation according to the KESS score. Participant can communicate and understand English. Participant has a body mass index (BMI) between 18.5 and 34.9kg/m2 (bounds included).  Exclusion Criteria:  Dependant use of opioid-based medications. New use of prokinetic therapy during the study. Use of antibiotics in the last 4 weeks. Use of probiotics in the last 2 weeks. Organic gastrointestinal disease, including inflammatory bowel disease (IBD), coeliac disease and diverticulitis. Participant has known mechanical obstruction of the GI tract. Participant has diabetes. Participant has any hepatic disease. Participant has any disease of the CNS. Participant has had previous abdominal or colorectal surgery including appendectomy, cholecystectomy, and hysterectomy. Participant has intake of ERME for 2 weeks before the study.