Carrageenan
Carrageenans are a family of polysaccharides extracted from seaweed. Their shape allows them to gel at certain temperatures, making them useful as stabilizing and thickening agents in infant formula, chocolate milk, cottage cheese, ice cream, jelly and diet soda.
Some animals have shown that large amounts of carrageenan can cause ulcerations and inflammation in the intestines. However, the small amounts found in food appear safe.