The result is a bit unexpected because many studies of individual vitamins have found they do not help prevent chronic diseases and some have even caused problems.
This new study involved almost 15,000 healthy older, male doctors who were followed for more than a decade.
Half took the multivitamin Centrum Silver and the others took a placebo. Those taking the vitamins had a modest 8 percent reduction in cancer cases.
But, the majority of men in the study were healthy, non-smokers, and experts aren't sure if these cancer benefits will apply to the general public.