Caffeine is a bitter white crystalline xanthine alkaloid that acts
as a psychoactive stimulant drug and a mild diuretic (speeds up
urine production) in humans and other animals. Caffeine was
discovered by a German chemist, Friedrich Ferdinand Runge, in 1819.
He coined the term "kaffein", a chemical compound in coffee, which
in English became caffeine. Caffeine is also called
guaranine when found in guarana, mateine when found
in mate, and theine when found in tea; all of these names
are synonyms for the same chemical compound.
