<unk>  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.<unk>  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<unk> .<unk>  is also<unk> lled 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.<unk>  is found in varying quantities in the beans, leaves, and fruit of over 60 plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. It is most commonly consumed by humans in infusions extracted from the beans of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut or from<unk><unk> o. Other sources include yerba mate, guarana berries, and the Yaupon Holly.
In humans,<unk>  is a central nervous system (CNS) stimulant, having the effect of temporarily warding off drowsiness and restoring alertness. Beverages containing<unk> , such as coffee, tea, soft drinks and energy drinks enjoy great popularity.<unk>  is the world's most widely consumed psychoactive substance, but unlike most others, it is legal and unregulated in nearly all jurisdictions. In North America, 90% of adults consume<unk>  daily. The U.S. Food and Drug Administration lists<unk>  as a "Multiple Purpose Generally Recognized as Safe Food Substance". One 2008 study suggested that women consuming 200 milligrams or more of<unk>  per day had about twice the miscarriage risk as women who drank none, while another 2008 study found no link between miscarriage and<unk>  consumption.
Caffeine
Salsalate
Allyl chloride
Methacholine
Methyl salicylate
Nicotine 
Nicotine
Nitroxoline