What does gluten do to people who are suffering from celiac disease?

Intestinal allergies: Celiac disease (gluten allergy) occurs in a person who may have a genetic tendency to react abnormally to gluten (a protein in wheat, barley, and rye). Something causes his immune system to over-react to gluten. Later, when he eats foods containing gluten, his immune system reacts with the intestine that is digesting the gluten, thus causing intestinal problems and abnormal digestion.

Destroys the gut: Antibodies to a protein in cereals, an enzyme and the cells lining the small intestines cause inflammation that destroys the those cells. The result is abdominal pain, flatulence ("gas"), diarrhea. Some patients who labeled as having "irritable bowel syndrome" actually have celiac disease when tested for it. Such patients may also develop a rash with blisters that look like herpes.

Gluten: Symptoms may include but are not limited to: diarrhea, constipation, fatigue, abdominal pain, cramps , rash (dermatitis herpetiformis) iron deficiency anemia. Treatment for celiac disease is gluten-free diet which generally resolves symptoms. Failure of symptoms to resolve usually means non adherence to the diet.