Small intestinal obstruction refers to a partial or complete blockage of the small intestine. If the small bowel is functioning properly, digested items will continue to pass into the large intestine. A partial or complete obstruction in the small bowel may prevent contents from passing. As a result, waste materials and gases accumulate in the area above the blockage. It may also prevent the absorption of nutrients and fluids. Conditions affecting the intestines are referred to as "colonic illnesses." This field includes diseases such as irritable bowel syndrome (Crohn's disease and ulcerative colitis), diverticular disease, and colon cancer.