Tomatoes contain lycopene which is an antioxidant. Other red items like watermelon and pink grapefruit also contain lycopene.
I like tomatoes raw in a salad and cooked in soups. Occasionally, I'll even eat one whole with a little salt. But cooked tomatoes provide more lycopene than raw tomatoes.
Lycopene, along with all of the other chemical substances found in tomatoes, is good for the whole body. It's especially known to help prevent cancer but, no doubt, it's good for everything.