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Caffeine Overdose: How Much Is Too Much?

Overview of Caffeine Overdose

Caffeine is a stimulant found in various foods, drinks, and other products. It’s commonly used to keep you awake and alert. Caffeine is technically a drug, and some of the most popular beverages in the United States, such as coffee, tea, and soda, have significant amounts of caffeine in them.

According to Mayo Clinic, the recommended amount of caffeine is usually 400 mg per day for healthy adults. Caffeine overdose may occur if you ingest more than this amount. However, a safe amount of caffeine differs for everyone based on age, weight, and overall health. This makes it difficult to know the exact amount of caffeine that can lead to overdose. For example, adolescents should limit themselves to no more than 100 mg of caffeine a day.

The chart below shows how much caffeine is found in a serving size of some common sources of caffeine, according to the Center for Science in the Public Interest.

Serving sizeCaffeine (mg)
Black coffee12 oz.260
Black tea8 oz.30-80
Soda12 oz.30-70
Red Bull8.3 oz80
Chocolate bar (dark)1.45 oz20
NoDoz caffeine tablets1 tablet200
Excedrin Migraine1 tablet65

A caffeine overdose can be life-threatening in the most severe cases, but many people only notice some unpleasant symptoms that go away once the caffeine is excreted from the body.

Check out a visualization of how caffeine affects the body »

Causes and Risk Factors of Caffeine Overdose

A caffeine overdose occurs when you take in too much caffeine through drinks, foods, or medications. However, some people can ingest well above the daily recommended amount each day without issue. This isn’t recommended because high caffeine doses can cause major health issues, including irregular heartbeat and seizures.

If you rarely consume caffeine, your body may be especially sensitive to caffeine, so avoid ingesting too much at one time. Even if you regularly consume large amounts of caffeine, you should stop when you feel any unpleasant symptoms.

What Are the Symptoms of Caffeine Overdose?

Several types of symptoms occur with this condition. Some symptoms may not immediately alert you that you have had too much caffeine because they may not seem serious. For example, you may experience:

  • dizziness
  • diarrhea
  • increased thirst
  • insomnia
  • headache
  • fever
  • irritability

Other symptoms are more severe and call for immediate medical treatment. These more serious symptoms of caffeine overdose include:

  • trouble breathing
  • vomiting
  • hallucinations
  • confusion
  • chest pain
  • irregular or fast heartbeat
  • uncontrollable muscle movements
  • convulsions

Babies can also suffer from caffeine overdose. This can happen when breast milk contains excessive amounts of caffeine. Some mild symptoms include nausea and muscles that continually tense and then relax. More serious signs of caffeine overdose can accompany these symptoms, including vomiting, fast breathing, and shock.

If you or a child under your care is experiencing these symptoms, you’re advised to seek a doctor’s help for diagnosis and treatment immediately.

Diagnosing Caffeine Overdose

If you suspect a caffeine overdose, let your doctor know of any amount of caffeinated items you consumed prior to having symptoms.

Your breathing rate, heartbeat, and blood pressure will also likely be monitored. Your temperature may be taken, and you may be given a urine or blood test to identify the drugs in your system.

Treatment for Caffeine Overdose

Treatment is meant to get the caffeine out of your body while managing the symptoms. You may be given activated charcoal, a common remedy for drug overdose, which often prevents the caffeine from going into the gastrointestinal tract.

If the caffeine has already entered your gastrointestinal tract, you may be offered a laxative or even a gastric lavage. A gastric lavage involves using a tube to wash the contents out of your stomach. Your doctor will likely choose the method that works fastest to get the caffeine out of your body.

During this time, your heart will be monitored through an EKG (electrocardiogram). You may also receive breathing support when necessary.

If the symptoms are mild, you may be able to wait until the caffeine is no longer in your body or treat the overdose yourself. Some home treatments for caffeine overdose include drinking water, mild exercise, and eating foods high in potassium or magnesium, such as bananas or dark leafy greens.

Home treatment may not always accelerate your body's metabolism of the caffeine. If you’re unsure whether or not you need treatment, call Poison Control at 1-800-222-1222 and describe your symptoms. If your symptoms sound severe, you’ll likely be advised to go to the local hospital for immediate treatment.


Avoid the consumption of excessive amounts of caffeine to prevent a caffeine overdose. In most cases, you shouldn’t have more than 300 mg of caffeine per day and even less if you’re particularly sensitive to caffeine.


Caffeine overdose can usually be treated with no long-term health problems, but this condition can be deadly, especially for younger patients, such as infants and toddlers. Caffeine overdose can also worsen pre-existing health conditions, such as anxiety. A review has connected the effects of excessive caffeine with that of other drugs, such as amphetamines and cocaine.

When treatment is given too late, there may be irreversible health problems and even death. You should at least call the American Association of Poison Control Centers (AAPCC) at 1-800-222-1222 if you suspect a caffeine overdose.

Content licensed from:

Written by: Autumn Rivers and Timothy Jewell
Published on: Oct 27, 2015on: Jun 12, 2017

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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