Can You Overdose on Caffeine?

By Theresa Stahl, RD, LDN

Reviewed by QualityHealth's Medical Advisory Board

According to the National Institutes of Health (NIH), caffeine is a substance that exists naturally in certain plants. It is found in the leaves, seeds and fruits of more than 60 plants, including cocoa beans, coffee, tea leaves, and kola nuts.

It can also be produced synthetically and used as an additive in foods and beverages and is currently showing up almost everywhere in products ranging from gum to water to candy bars. It is frequently added to medications including pain relievers, appetite suppressants and cold medicines.

Here are some interesting facts about caffeine:

It is a stimulant and is commonly used as a treatment for fatigue and drowsiness.
It is a diuretic, which increases urination.
It is absorbed quickly and passes to the brain, which is the reason that it seems to affect you fast.
It has no flavor and can be removed from a product by the process called decaffeination.
It may be used as a treatment for migraine headaches.
Contrary to popular belief, caffeine does not reduce the effects of alcohol.
It is mildly addictive and if you stop your intake abruptly, you may experience withdrawal symptoms, such as headaches and depressed mood.

According to NIH, moderate intake of caffeine is not associated with any health risk. Excessive intake, however, can lead to increased heart rate, excessive urination, nausea, vomiting, restlessness, anxiety, depression, tremors and difficulty sleeping. Two-three 8 oz cups of coffee (or about 250 mg.) per day is considered a moderate amount of coffee. Ten 8 oz. cups per day is considered excessive. Some people experience harmful symptoms with less than this.

Pregnant women and people with coronary heart disease or peptic ulcers may be advised by their health care providers to restrict or avoid using caffeine and many drugs interact with caffeine. Check with your pharmacist about potential interactions with caffeine whenever you take medications.

Here is the caffeine content of common beverages and foods: