Does Lily of the Desert Aloe Vera Jelly cause cancer? I read somewhere that some ingredient in it cause cancer.

Carregeenan. The hoopla is over carregeenan, a seaweed gel that's a thickener. The stuff is widespread in food. There are some old papers in which big doses of a form not used in food served as a promoter, but anything can do that. There are some "scare" sites with made-up stuff, and one reviewer is still concerned, but most folks consider the stuff a non-carcinogen. You can't avoid everything folks warn about.