Oct. 11, 2006 -- Sticking to decaf isn't going to eliminate caffeine from your coffee.

That's according to a new study that shows even decaffeinated coffee comes with at least a small dose of caffeine.

"If someone drinks five to 10 cups of decaffeinated coffee, the dose of caffeine could easily reach the level present in a cup or two of caffeinated coffee," says researcher Bruce A. Goldberger, PhD, of the University of Florida, in a news release.

Researchers say caffeine is the most widely consumed drug in the world, and coffee is a major source. Despite this, there are few guidelines about how much caffeine is too much, and even low doses may adversely affect some people.

People with certain medical conditions, including high blood pressure and heartarrhythmia, as well as those taking certain prescription medications are advised to avoid or limit caffeine.

In an effort to abstain from caffeine, many people turn to decaffeinated coffee, but researchers say they may be unaware that these decaf beverages also contain caffeine.