Does beta carotene fight cancer?

Maybe: Please forgive this senior physician's frankness. The data on carotenes and lycopenes is so massive, so contradictory, is so tied up with the politics of "healthy diet", and makes so little sense scientifically that your question cannot be answered. In science, the stuff that's really true is generally established quickly. I love eating carrots, but would not spend money supplementing carotene.

Antioxidant power?: Beta carotene has been touted as an anti cancer agent for its antioxidant properties. However, in a large prospective cancer prevention trial using it as a supplement in smokers, the incidence of lung cancer was higher in people taking beta carotene. Beware of unsubstantiated claims of certain food supplements since they could cause more harm than good!