INTRODUCTION: Cystic Fibrosis (CF), Ulcerative Colitis (UC), and Crohn's Disease (CD) manifest as various, multiple symptoms from malfunctioning and/or damaged gastrointestinal tract, which plague the patients. These symptoms result from the dysfunctional expression products of the specific mutations of the genes, which either manifest upon birth (CF) or later in life in immuno-genetically susceptible individuals as inflammatory bowel diseases (IBD). They all may potentially lead to malnutrition of the patients. Since only correcting the mutated genes, may cure these diseases permanently, the works on the future safe gene therapies continue vigorously. However, provision of the necessary nutrients to the suffering patients is the requirement for an effective, supportive care at present. In this realm, we have developed a model of the diseased gastrointestinal tract aimed to guide designing and testing various nutritional therapies.MATERIALS AND METHODS: It is well known that inflammatory bowel diseases induce crypts within the patients' gastrointestinal tract. Therefore, we have bioengineered, a novel, three-dimensional model of the gastrointestinal tract to evaluate the rheology of different types of nutrients. The model was assembled out of the bio-inert polymer tube with openings leading to vials of different shapes and sizes, as the simulation of the gastrointestinal tract altered by the diseases to contain multiple crypts.RESULTS AND CONCLUSIONS: The newly developed three-dimensional model effectively simulates the structure and functions of the gastrointestinal tract of the patients with mild and severe Ulcerative Colitis, Crohn's Disease, and Cystic Fibrosis. This model should allow us to design and test different nutritional supplements, with properties complementing the pathologically altered by the diseases functionalities of the patients' gastrointestinal tracts. Therefore, it should help us to design the effective supportive therapies; thus to prevent the patients' malnutrition.