One 8.4 fluid ounce can of Red Bull contains about 80 mg of caffeine. This is roughly the same amount of caffeine contained in a cup of coffee.
Caffeine is used for its stimulating effects on the human body. It affects the central nervous system by stimulating cognitive functions and can be used to "wake up" the body and brain when it otherwise would be lacking in energy or cognitive efficiency. Caffeine occurs naturally in a number of food products. It can be consumed in solid food forms, such as dark chocolate, but is often consumed in liquid form, such as tea, coffee, sodas and energy drinks. Red Bull is often consumed for its relatively high caffeine content.