Ketchup (or less commonly catsup) also known as Red Sauce or Tomato Sauce is a condiment, usually made with ripened tomatoes. The basic ingredients in modern ketchup are tomatoes, vinegar, sugar, salt, allspice, cloves, and cinnamon. Onions, celery, and other vegetables are frequent additions.
Ketchup started out as a general term for sauce, typically made of mushrooms or fish brine with herbs and spices. Mushroom ketchup is still available in some countries, such as the UK. Some popular early main ingredients include blueberry, anchovy, oyster, lobster, walnut, kidney bean, cucumber, cranberry, lemon, celery and grape.
The largest major commercial distributors of ketchup in the United States are the H. J. Heinz Company, Hunt's, Del Monte Foods, and Red Gold.
Ketchup is often used for chips (french fries), hamburgers, sandwiches and grilled or fried meat. Ketchup with mayonnaise forms the base of Thousand Island dressing and fry sauce. Ketchup is also typically used as a base for barbecue sauce, especially in the Southern United States.