Researchers at the University of Ulster in Northern Ireland have shown that watercress can help to prevent cancer.

In a study published in the February 2007 edition of the American Journal of Clinical Nutrition the researchers found that adult smokers and non-smokers who added 85 grams of watercress to their diets had increased levels of antioxidants in their blood and reduced free radical damage to the DNA in their white blood cells.  

University of Michigan researchers announced at the annual meeting of the American Association of Cancer Research that ginger can kill ovarian cancer cells.

The study also found that the spice had the added benefit of stopping the cells from becoming resistant to treatment.

Chili peppers 'kill prostate cancer'

Capsaicin, the ingredient which makes chilies and other red peppers hot, also makes prostate cancer cells commit suicide.