The primary ingredient in ketchup is tomatoes. Ketchup is a popular condiment that typically consists of tomato paste, vinegar, sugar, and a blend of spices and seasonings. The tomatoes provide the base and give ketchup its distinctive red color and rich flavor. Various recipes may also include ingredients like onion, garlic, and allspice. Ketchup is often used as a condiment for hamburgers, fries, and other fast foods, making it a staple in many households. Its sweet and tangy profile has made it a favorite across various cuisines worldwide.