C-Affeinated kids.

True or false: A cup of Haagen-Dazs coffee ice cream has more caffeine than a can of Coke. Reward yourself with a spoonful of ice cream if you said "true."

We discovered that fact during a recent analysis of the caffeine content of 25 products. The results indicate that people, especially children, can easily consume enough caffeine to leave them jittery and anxious. And because foods and drinks are not required to list how much caffeine they contain, it can be hard to gauge how much you or your kids are getting. Some of the products we tested, such as iced teas and colas, are obvious caffeine carriers. But you might be surprised by the amount bidden in others:

* Mountain Dew has more caffeine than Coke or Pepsi; Sunkist Orange has nearly as much as the colas, though Minute Maid Orange has none.

* Trendy vitamin waters can harbor caffeine, too. Ounce for ounce, Glaceau Vitaminwater Energy Tropical Citrus has about twice as much caffeine as Nestea Iced Tea.

* A 9.5-fluid-ounce bottle of Starbucks Coffee Frappuccino, a sweet, milky drink delivers almost as much caffeine as three 12-ounce cans of Coke.

* An 8.4-ounce can of the energy drink AMP has about three times as much caffeine as the same amount of SoBe Energy Citrus Flavored Beverage. Many energy drinks (and some fortified waters) also include guarana, a caffeine-containing herb, and ginseng, which may intensify caffeine's effects.

In addition to our analysis of caffeine content, we held taste tests to see whether students preferred regular Coca-Cola Classic or Pepsi to their caffeine-free counterparts (see opposite page).