A Chicago hot dog – as served in Chicago, and its surrounding suburbs – is a steamed or boiled all-beef, natural-casing hot dog on a poppy seed bun, topped with mustard, onion, sweet pickle relish in fluorescent green, a dill pickle spear, tomato slices or wedges, sport peppers and a dash of celery salt — but no ketchup. (Also called a "Chicago-style hot dog")