Carrots contain a natural compound called falcarinol, which protects the carrot from fungal diseases. Researchers from The University of Southern Denmark studied three groups of 24 rats with precancerous tumors. The first group was the control and did not consume falcarinol. The second group consumed feed and raw carrots. The last group consumed feed with falcarinol added to it.
After 18 weeks, the rats that received either falcarinol or raw carrots in their diet were one-third (1/3rd) less likely to develop cancerous tumors than the control group.
J. Agric Food Chem. 2005 Mar 9:53(5): 1823-7.