Carrageenan is extracted from red seaweed and used as a thickener and gelling agent, especially in wet/canned pet food. Animal studies have shown carrageenan can cause intestinal inflammation, ulceration, and potentially contribute to inflammatory bowel disease. The food industry distinguishes "food-grade" carrageenan from "degraded" carrageenan (poligeenan), but in vivo degradation in the gut may convert one to the other. Many premium wet pet foods now exclude carrageenan.