Celiac disease is a condition of the digestive system. It is a digestive disorder that occurs as a result of eating gluten. Gluten is a protein that is found in foods such as wheat, rye, and barley. People with celiac disease have a negative reaction to eating gluten in which case their immune system becomes inflamed and damaged. Eating gluten causes an immune response in your small intestine. The small intestine becomes inflamed and is unable to process certain nutrients. Over time, this can cause problems such as bloating, diarrhea, weight loss, and even more severe issues involving the liver, nervous system and bones.