Tomatoes are botanically defined as fruits because they form from a flower and contain seeds. Still, they're most often utilized like a vegetable in cooking.
 
Tomato is used for preventing cancer of the breast, bladder, cervix, colon and rectum, stomach, lung, ovaries, pancreas, and prostate. It is also used to prevent diabetes, diseases of the heart and blood vessels (cardiovascular disease), cataracts, and asthma.