This will make you smile:
In the late 18th century, King Gustavus III of Sweden was rumored to have carried out a strange experiment to find the harmful health effects of coffee. Condemned to death, two identical twins had their sentences commuted to life in prison on the condition that one would drink three pots of coffee per day, and the other three pots of tea, for the rest of their lives. The only problem was that the doctors assigned to monitor the cases died before either of the patients did, their observations lost–as the story goes, the tea drinker died first, and there’s no record of the coffee-drinker’s death. The experiment proved nothing, suffering from a lack of rigor (to say the least).
Source: Uppsala University, “Coffee – rat poison or miracle medicine?”