Cocktail sauce in its simplest form is ketchup mixed with prepared horseradish (In the United Kingdom, Iceland, and Belgium, mayonnaise is usually mixed with the ketchup, similar to fry sauce). It is popularly served with steamed shrimp and seafood on the half shell. Many restaurants use chili sauce in place of ketchup.In most American oyster bars, cocktail sauce is the standard accompaniment for raw oysters and patrons at an oyster bar expect to be able to mix their own. The standard ingredients (in roughly decreasing proportion) are ketchup, horseradish, hot sauce (Tabasco, Louisiana, or Crystal), Worcestershire sauce, and lemon juice. A souffle cup is usually set in the middle of the platter of oysters along with a cocktail fork and a lemon slice. Often, the bottles of ketchup and other sauces are grouped together in stations every couple of feet along the counter, but in nicer oyster bars, patrons are served with their own ingredients.