guinness stout drinking pint RTXKFKDPaul McErlane/Reuters

Vegetarian and vegan drinkers, rejoice: By the end of this year, Guinness has said it will no longer use fish bladders to make its 256-year-old stout.

At issue is isinglass, a gelatin-like substance derived from the fish that helps filter the beer.

Guinness is certainly not alone in using animals in its product line, though.

Countless other companies rely on a dizzying variety of animal ingredients to manufacture their foods and beverages.

Here's a list of the most common — and surprising — classes of products to watch out for, and the non-vegetarian-friendly ingredients they might contain or rely on.

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