Up to 400 milligrams (mg) of caffeine a day seems safe for most adults. That's about the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two "energy shot" drinks. Keep in mind that the caffeine content in drinks varies widely.

Although we tend to associate caffeine most often with coffee or tea, the research below focuses mainly on the health effects of caffeine itself. Visit our features on coffee, tea, and energy drinks for more health information related to those beverages.

Caffeine is a natural chemical with stimulant effects. It is found in coffee, tea, cola, cocoa, guarana, yerba mate, and over 60 other products. Caffeine works by stimulating the central...

That morning cup of coffee feels routine, right? But the caffeine kick might not be. Consumer Reports tested popular coffees and found that caffeine can vary a lot. In some cases, just one large cup ...

CONCERNS OVER THE STRIKES IN IRAN CAUSING MARKETS TO PLUNGE DOWN TODAY. WELL, THAT MORNING CUP OF COFFEE FEELS PRETTY ROUTINE, RIGHT. BUT THE CAFFEINE KICK MIGHT NOT BE. CONSUMER REPORTS TESTED ...

WESH: How much caffeine is really in your coffee? | Consumer Report

Many people enjoy a cup of coffee or tea to give them a boost. But is it safe? Learn more about caffeine.