Nahidi et al. [3,4]. It is a lifelong condition, characterised by frequent disease relapses and remissions. Although genetics, the environment, and microbiota all play a part, the exact cause of CD or UC remains unknown and cures are unavailable [4] Therapy is designed to induce prolonged remission, which can often be achieved by a combination of corticosteroids and immunosuppressants. Corticosteroids constitute a AN2718 first line of treatment to manage the acute presentation and relapses [5]. Various immunomodulators including Azathioprine, Methotrexate, and thioguanine analogues are frequently AN2718 used for AN2718 maintenance therapy [5]. More recently biologic agents such as infliximab are being used in patients with AN2718 both steroid refractory and dependant luminal disease and fistulising and extraintestinal CD [6]. Infliximab is an antitumour necrosis factor alpha (TNF) chimeric antibody and acts by inhibiting the action of TNF[6,7]. Unfortunately most of these treatment options, though effective, come at a significant cost to the patient in terms of adverse effects. Corticosteroids are limited in their use by risk of infection, osteoporosis, hypertension, growth retardation, poor mucosal healing, and early relapses on cessation of therapy [8]. This is especially problematic in paediatric patients who may experience significant growth retardation and osteoporosis with Notch1 steroid therapy [912]. Prolonged immune suppression AN2718 with immunomodulators is also concerning owing to the risk of opportunistic infections besides problems with hematologic disorders [13]. Biologic agents are limited by loss of efficacy over time due to the development of antibodies, as well as a risk of local reactions, anaphylaxis, and vasculitis [6]. Moreover the reported risk of lymphomas especially in young adult males on concomitant Azathioprine and infliximab, albeit low, further limits their use [14,15]. Exclusive enteral nutrition (EEN) is a nutritional therapy used for the treatment of Crohn’s Disease [16]. In general terms, it is used for induction of remission and is achieved by a period of 68 weeks of exclusive liquid feeding with either elemental or polymeric formulae. The patients are not allowed to have any other dietary items except plain water and some beverages. EEN offers little risk but appears to be relatively underused compared to other modalities, except in paediatric practice. The purpose of our review was to examine the history of its introduction to current practice, relative efficacy, and possible mechanisms of action. In order to carry out this review, we conducted a PubMed search using key words enteral nutrition and inflammatory bowel disease which revealed 732 publications. Of these 100 were found to be relevant with 50 providing useful information which were used in this report. == 2. History of EEN == Nutritional therapy for CD has been employed ever since the condition was first described in 1932 [17]. The earliest reports of the use of nutritional therapy indicate that it was used primarily as a means to improve nutrition in debilitated patients unfit for surgical management. This nutritional therapy was in the form of a high protein, high carbohydrate, low residue diet with additional iron and supplements for specific nutritional deficiencies [1820]. Specific beneficial outcomes from nutritional therapy were viewed as being due to improvement in nutritional status and the possibility that nutritional therapy might have a direct therapeutic value was not considered. Corticosteroids became pivotal to pharmacological management with a high protein, high carbohydrate diet used as an adjunct to provide gut rest and improve the nutritional status [20,21]. The possible efficacy of a nutritional-based therapy for direct treatment of CD was first reported by surgeons in the 1970s when Votik et al. [22] treated 13 patients with elemental formula 17 times over a period of 22 days. All but one of the patients tolerated the formula and demonstrated not only weight gain but there appeared to be an improvement in inflammatory indices. Logan et al. [23] subsequently found evidence of diminished gut lymphocyte and protein loss when enteral feeds were used in patients with extensive small bowel disease. A subsequent controlled trial by O’Morain [24] suggested clinically equivalent or even superior efficacy of elemental feeds over steroids for adults with relapses of CD. A subsequent meta-analysis of a mixture of 8 trials involving 413 patients published up to 1993 suggested that enteral feeds were significantly inferior on an intention to treat basis compared to corticosteroids in producing a clinical remission (pooled odds ratio 0.35; 95% confidence intervals, 0.230.53) [25] Clinical response to enteral feeds ranged from 53 to 80% by 36 weeks. A large part of this difference related to feed intolerance, with.