A bitter white alkaloid, C8H10N4O2, often derived from tea or coffee and used in medicine chiefly as a mild stimulant and to treat certain kinds of headache. It is also present in most cola beverages. The drug increases the blood pressure, stimulates the central nervous system , promotes urine formation, and stimulates the action of the heart and lungs. Caffeine is used in treating migraine, increases the potency of analgesics such as aspirin, and can relieve asthma by widening the bronchial airways.
Caffeine is produced commercially chiefly as a by-product in making decaffeinated coffee.
Cola drink bottlers and canners receive FDA dispensation not to list caffeine as an ingredient. Cola drinks generally have 4 milligrams of caffeine per fluid ounce, coffee 12 to 16. Caffeine is a weak mutagen, for this reason. At least that is how the folks at Starbucks and the Family Christian Center in Munster, Indiana feel. The church is the first in the U.S. to open a Starbucks in its lobby.