Caffeine is widely consumed and is found naturally in the leaves, seeds, and fruits of more than 60 plants, including tea leaves, kola nuts, coffee, and cocoa beans. It is in coffee, tea, chocolate, cocoa and many carbonated beverages such as colas. It can also be produced synthetically.

Caffeine is frequently added to over-the-counter medications such as pain reliever appetite suppressants, and cold medicines. Caffeine has no flavor and can be removed from a food by a chemical process called decaffeination.

Caffeine is absorbed very quickly from the gastrointestinal tract and then distributed in the various body tissues. After absorption, it passes into the central nervous system. "Caffeine sensitivity" refers to the amount of caffeine that will produce negative side effects. This amount will vary from person to person. Caffeine does not accumulate in the bloodstream nor is it stored in the body. It is excreted in the urine many hours after it has been consumed. Caffeine will not reduce the effects of alcohol, although many people still believe a cup of coffee will "sober up" an intoxicated person.

Caffeine may be used as a treatment for migraine headaches and in relieving, for a short time, fatigue or drowsiness.

There is no human requirement for caffeine in the diet. Moderate caffeine intake, however, is not associated with any health risk. Three 8oz cups of coffee (250 milligrams of caffeine) per day is considered an average or moderate amount of caffeine. Ten 8oz. cups of coffee per day is considered excessive intake of caffeine.

A child's caffeine consumption should be closely monitored. Although caffeine is safe to consume in moderation, it may negatively affect a child's nutrition. Caffeinated beverages may be replacing nutrient dense foods such as fruit juices and milk. A child may also eat less because caffeine acts as an appetite suppressant. Caffeine can be completely restricted in a child's diet since there is no nutritional requirement for it. This may be necessary for a hyperactive child, as caffeine is a central nervous stimulant.

Pregnant women and people with coronary heart disease or peptic ulcers may be advised by their health care provider to restrict or avoid using caffeine.

Many medications will interact with caffeine. Consult with your health care provider or pharmacist about potential interactions with caffeine whenever you take medications..

Excessive caffeine intake can lead to a fast heart rate, dieresis (excessive excretion of fluids) nausea and vomiting, restlessness, anxiety, depression, tremors, and difficulty sleeping.

The effect of caffeine on health has been widely studied. In particular, the effects of caffeine on fibrocystic breast disease, cardiovascular disease, birth defects, reproductive function, and behavior in children have been closely examined. A 1984 statement from the American Medical Association Council on Scientific Affairs stated "Moderate tea or coffee drinkers probably have no concern for their health relative to their caffeine consumption provided other lifestyle habits (diet, alcohol consumption) are moderate as well." This statement puts caffeine use in perspective.