Once the test solution has been ingested, blood samples will be obtained via a cannula which is placed in a vein, usually in the arm, prior to the start of the test, to allow further sampling without causing discomfort to the patient. A total of 15 samples will be obtained over a 5 hour period, with intervals ranging between 20-30mins, of not more than 6mls per sample. At the end of the test, at a 5 hour interval, a further urine sample will be collected to allow for intestinal functional testing. This is exactly the same procedure as that specified in the approved 'The Gut-Liver Axis in Liver Disease & Liver Transplantation' study (REC ref: 12/LO/1417).