'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 Irish Coffee has certain benefits and side effects. The content of caffeine in Irish Coffee is 155.00 mg. Caffeine can be effective on headaches and can increase alertness but, very high doses of Irish Coffee caffeine can have adverse effects on our body. So, Irish Coffee caffeine content should be as low as possible. Also, get to know caffeine content of other products like Irish Coffee vs Affogato, Coffee vs Affogato.