Biotin deficiency is often overlooked in patients with Inflammatory Bowel Disease, but it may have profound implications in the GI tract. Biotin is a water-soluble vitamin that must be obtained from exogenous sources and is involved in the metabolism of fatty acids, glucose and amino acids. Recently, we have studied the impact of biotin deficiency, induced by dietary or genetic methods, in mice and have found that they develop growth retardation, decreased bone density, and histological changes in intestine that are similar to what we find in patients with IBD.