Caffeine is a nitrogen-containing organic compound that is classed as an alkaloid and known by the IUPAC name 1,3,7-trimethylpurine-2,6-dione.
In common with many other alkaloids, it is a naturally occurring compound of plant origin that has strong biological effects on animal and human organisms.
One of the most common sources of human caffeine consumption is coffee drinks, and its stimulant effect on the central nervous system is considered to promote alertness and reduce feelings of drowsiness.