What happens if I drink too much Earl Grey tea?

October 17, 2025 •

4 min read

According to a case study published in The Lancet, a man who drank four liters of Earl Grey tea daily developed severe muscle cramps and neurological symptoms which subsided upon reducing his intake. This unusual, but important, case highlights the question: what happens if I drink too much Earl Grey tea? While generally safe in moderation, excessive consumption can lead to notable side effects from both its caffeine and bergamot oil content.

Quick Summary

Excessive consumption of Earl Grey tea can cause adverse effects due to its caffeine and bergamot content, including severe muscle cramps, jitters, insomnia, reduced iron absorption, and increased risk of kidney stones. These issues stem from specific compounds in the tea affecting nerve function, mineral balance, and sleep patterns.

Key Points

Bergamot Toxicity: Extreme overconsumption of Earl Grey can lead to bergamot toxicity, causing severe muscle cramps, twitching, and tingling sensations.
Caffeine Overload: The caffeine in Earl Grey can cause anxiety, insomnia, jitters, and headaches if consumed in excessive quantities.
Reduced Iron Absorption: High tannin levels in black tea can inhibit the body's absorption of non-heme iron, potentially affecting individuals with anemia or vegetarian diets.
Kidney Stone Risk: The oxalate content in black tea can increase the risk of calcium oxalate kidney stones, especially for those with a predisposition.
Moderation is Essential: Limiting intake to 2-4 cups per day is recommended for most healthy adults to avoid potential side effects from caffeine and bergamot oil.
Neurological Symptoms: In rare but documented cases of extreme intake, bergapten in bergamot can block potassium channels, leading to neurological issues like paraesthesia and blurred vision.

The Double-Edged Brew: Caffeine and Bergamot Oil

Earl Grey is beloved for its distinct citrus aroma, which comes from bergamot oil, combined with a black tea base. This delightful flavor comes with two main active compounds that can cause issues when consumed in large quantities: caffeine and bergamot oil. Understanding the effects of each is crucial for any frequent drinker.

The Risks of High Caffeine Intake

As a black tea, Earl Grey contains caffeine, typically 40-70 mg per cup, though this can vary with brewing method and strength. Consuming too much caffeine, whether from tea or coffee, can lead to a range of unpleasant symptoms, especially for those sensitive to it.

Anxiety and jitters: High caffeine intake can trigger nervousness, anxiety, and a shaky sensation.
Insomnia and poor sleep quality: Consuming caffeine too close to bedtime can disrupt sleep cycles and lead to restlessness.
Headaches: For some, large doses of caffeine can trigger headaches or even migraines, while for others, withdrawal can cause a headache.
Digestive upset: Caffeine can increase stomach acid production, leading to heartburn, acid reflux, or general gastrointestinal discomfort.

The Specific Danger of Bergamot (Berga**pten)

What sets Earl Grey apart from other black teas is the addition of bergamot oil, which contains a compound called bergapten. While benign in small doses, excessive bergapten can interfere with potassium channels in nerve cells, leading to serious neurological symptoms.

Muscle cramps and fasciculations: The most widely reported side effect of bergamot toxicity is severe and involuntary muscle cramps and spasms. The famous Lancet case study detailed a man experiencing widespread muscle cramps and twitching from drinking excessive Earl Grey.
Paraesthesia: This is a sensation of tingling, prickling, or numbness, often described as “pins and needles.” It has been noted in cases of bergamot overconsumption.
Blurred vision: Another reported neurological symptom in cases of bergapten toxicity is blurred vision.

Beyond Caffeine and Bergamot: Other Adverse Effects

Overconsumption of Earl Grey can trigger several other nutritional and physiological issues, primarily linked to the black tea base itself.

Tannins and Iron Absorption

Black tea is rich in tannins, natural compounds that give tea its characteristic bitterness and color. Tannins can bind to non-heme iron (the iron found in plant-based foods) in the digestive tract, significantly reducing its absorption by the body.

This is a particular concern for individuals at risk of iron deficiency, such as vegans, vegetarians, and those with anemia.
To minimize this effect, it is recommended to drink tea between meals rather than with them.

Oxalates and Kidney Stone Risk

Black tea has a moderate to high level of oxalates. For most people, this isn't an issue, but for individuals prone to forming calcium oxalate kidney stones, excessive black tea consumption could increase their risk. While moderate consumption is fine, heavy drinkers with a history of kidney stones should be cautious.

Comparison of Earl Grey vs. Other Teas


Feature	Earl Grey Tea	Green Tea	Herbal Tea (e.g., Peppermint)
Caffeine	Moderate to high (40-70 mg/cup)	Low to moderate (30-50 mg/cup)	Typically caffeine-free
Bergamot	Yes (contains bergapten)	No	No
Tannins	High	Lower than black tea	None to low
Oxalates	Moderate to high	Significantly lower	Varies, often low
Muscle Cramps Risk	Possible with extreme overconsumption	No	No
Iron Absorption	Can inhibit non-heme iron	Can inhibit non-heme iron	Minimal effect

How Much is Too Much?

For the average, healthy individual, enjoying 2-4 cups of Earl Grey daily is generally considered safe and poses minimal risk. The severe symptoms of bergamot toxicity are typically associated with very high intake, often 4 liters or more per day. Individual tolerance to caffeine and tannins varies, so it's important to pay attention to your body's signals. If you experience digestive issues, jitters, or sleep problems, consider reducing your intake or switching to a decaffeinated version.

Warning signs of Earl Grey overconsumption

Persistent or unusual muscle twitching or cramps.
Unexplained anxiety, restlessness, or insomnia.
Recurring headaches, especially after prolonged consumption.
Increased heartburn or stomach upset.
Symptoms of iron deficiency (e.g., fatigue) in individuals with a high tea intake.

Conclusion: Moderation is Key

While a moderate amount of Earl Grey tea can be a safe and pleasant part of a balanced diet, overindulgence carries real risks. Excessive intake can lead to problems stemming from its caffeine content, as well as the unique bergamot oil, which can cause severe neurological symptoms in rare cases. Additionally, the tannins and oxalates in the black tea base can affect mineral absorption and increase kidney stone risk for susceptible individuals. The key is moderation. If you're a heavy tea drinker, consider reducing your intake or exploring alternatives like herbal teas or decaf options to avoid potential complications. As always, listening to your body and adjusting your habits is the best approach to maintaining good health. For more information, please consult a trusted health resource like WebMD.

Frequently Asked Questions

While individual tolerance varies, drinking more than 4 cups of Earl Grey tea per day is often considered excessive. The most severe symptoms of bergamot toxicity have been reported in individuals consuming 4 liters (about 16 cups) or more daily.

Yes, excessive consumption of Earl Grey tea has been linked to muscle cramps. The bergamot oil in the tea contains a compound called bergapten, which can interfere with potassium absorption and cause muscle spasms.

Yes, due to its caffeine content, drinking too much Earl Grey, especially in the afternoon or evening, can disrupt sleep patterns and lead to insomnia.

Yes, the tannins in black tea can inhibit the absorption of non-heme iron from plant-based foods. It is recommended to drink Earl Grey between meals rather than with them if you are concerned about iron levels.

In small, moderate quantities found in tea, bergamot oil is safe for most. However, in extremely large doses, the bergapten in bergamot can be toxic and cause serious neurological side effects.

Switching to decaffeinated Earl Grey eliminates the caffeine-related risks like jitters and insomnia. However, the bergamot oil and tannins remain, so it is still wise to consume it in moderation.

Due to its moderate to high oxalate content, excessive consumption of Earl Grey tea can potentially increase the risk of kidney stones, particularly for individuals who are susceptible to them.

In documented cases, such as the one in The Lancet, the muscle cramps and other neurological symptoms completely subsided after the individual stopped drinking excessive amounts of Earl Grey tea.

For those concerned about the side effects of Earl Grey, alternatives with lower caffeine and oxalate levels include green tea, white tea, or herbal teas like chamomile and peppermint.