Celiac disease is a digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have celiac disease cannot tolerate gluten, a protein in wheat, rye, and barley.

Gluten is found mainly in foods but may also be found in everyday products such as medicines,
vitamins, and lip balms.

FOR MORE DETAILS http://digestive.niddk.nih.gov/ddiseases/pubs/barretts/