Caffeine is a stimulant drug acting on the brain and nervous system. It is found in coffee, most teas, cocoa, chocolate, cola and energy drinks.
It can make users feel more awake, and raise the heart rate and blood pressure. In larger amounts it can lead to feeling restless and anxious, headaches and can cause trouble getting to sleep or poisoning. Regular consumption may lead to withdrawal problems such as headache, fatigue, irritability, and lack of clarity in thinking.
Follow the links below to find trusted information about caffeine.
Last reviewed: February 2014