Celiac disease is an abnormal immune system reaction to gluten, a protein found in grains like wheat, barley, rye, and triticale (a wheat-rye cross). It damages the small intestine so that it can't do a good job of absorbing nutrients from your food.

If you have celiac disease, you need to avoid foods that contain gluten.

Celiac disease is also known as celiac sprue, gluten-sensitive enteropathy, and nontropical sprue.