Caffeine is a stimulant which has been loved the most by a human so far. Not only coffee but also tea, green tea, chocolate, Coke, and many other beverage and sweets include caffeine.
Caffeine is a drug which causes dependence on a human. Human is said not to become tolerant to its awakening effect. But, when quitting caffeine after regulatory taking, you may feel sleepy, dull, or tired.
In addition, it is not well known that caffeine has a toxic effect on your heart. It enhances the heartbeat, thus burdening the heart muscle. Elder people with heart diseases should be cautious to take a large amount of coffee.
In Japan, there was the first case reported regarding caffeine induced death last year. In this case, the victim was in the 20s and worked at midnight. He regularly took tablets including caffeine to kill his drowsiness. Approximately 182 micro-grams per cc of caffeine were detected in his blood sample in the investigation after death. This amount reached the fatal level.
It is not likely that the man of this case took caffeine for the suicidal purpose. On the other hand, it is possible he had had some cardiac diseases before taking caffeine. There is a variance of a dose of caffeine causing fatality. Anyway, this case tells us we should pay attention to taking a large amount of caffeine.
Recently, I read an article reporting an Australian café. This restaurant offers extremely strong coffee. According to this article, up to five grams of caffeine is included in the special coffee.
International Business Times: Australian cafe offering coffee 80 times stronger than an espresso
I think it is quite dangerous for you to take this beverage. The fatal dose of caffeine for a man is around ten to sixteen gram. Five gram could be critical for some persons. The café suggests drinkers to take this coffee with spending a couple of hours. Even if slowly absorbed, a high concentration of caffeine can cause trouble to your cardiac system.
I hope nobody will be harmed by this special coffee. And I do recommend you not to try it.