The average cup of coffee or tea contains 100 to 150 milligrams of caffeine, and a 12-ounce bottle of cola contains about 35 to 55 mg of caffeine. Among these facts is, caffeine is one of the worlds most widely used drugs. Anthropologists say that they used it as far back as the Stone Age. It is in one of the groups of stimulants called methylxanthine, or xanthine, which naturally occurs in plants. You d be surprised to know that beverages made from nuts, seeds or leaves of these plants are major sources of caffeine.
Caffeine is an alkaloid.
It is useful both socially and medically because of it s important effects on the brain, kidney, heart and respiratory system. Caffeine stimulates the nervous system and is helpful when treating cases of poisoning caused by central depressants such as alcohol or morphine. This reduces the flow of blood to the brain, relieving the pressure. Caffeine increases the flow of urine but is not used medically for this, partially because it isn t the most effective way to accomplish this effort. The drug stimulates the heart and relaxes the smooth muscle, especially the bronchial muscle.