'Everything will be fine once caffeine kicks in', is a common belief among tea coffee lovers. But do you know exactly what is caffeine? Caffeine mostly found in tea, coffee, cola and some chocolates is a type of drug that stimulates the nervous system of our body. Caffeine in Earl Grey Tea has certain benefits and side effects. The content of caffeine in Earl Grey Tea is 65.00 mg. Caffeine can be effective on headaches and can increase alertness but, very high doses of Earl Grey Tea caffeine can have adverse effects on our body. So, Earl Grey Tea caffeine content should be as low as possible. Also, get to know caffeine content of other products like Earl Grey Tea vs Affogato, Coffee vs Affogato.