Overview

Black tea, one of the most popular teas worldwide, is made from the oxidized leaves of the Camellia sinensis plant. It contains about half as much caffeine as a cup of brewed coffee. It also contains other chemicals, such as theaflavins, that may have effects in the body. Some people drink black tea to improve overall health, but its benefits for any health purpose are not well defined. Common side effects are caused by its caffeine content and include nervousness, trouble sleeping, an increased need to pee, or an upset stomach. Before drinking black tea, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is black tea used for?

Black tea is commonly consumed as a beverage. Some people drink black tea to increase energy levels and thinking skills. There is also interest in drinking black tea to improve overall health, but its benefits for this use are not well defined.

Note: Black tea is a beverage, which is regulated by the FDA. Learn more about the regulation of foods and beverages here. The FDA has not reviewed black tea extracts for safety and effectiveness. Learn more about dietary supplements here.

How does black tea work (mechanism of action)?

Black tea, one of the most popular teas worldwide, is made from the leaves of Camellia sinensis. These same leaves are used to make many popular teas, but each tea uses leaves that have been processed in a unique way. Black tea is made from leaves that have been fully oxidized. Oolong tea uses partly oxidized leaves. Another popular tea, called green tea, is made from fresh leaves that were heated right after they were picked. White tea, pu-erh tea, and yellow tea are also made from the leaves of Camellia sinensis.

These different processing methods give each tea its own distinctive color, flavor, and chemical profile. The different chemicals in each type of tea can change their effects in the body. For example, black tea contains the highest caffeine content of any of these teas. So, it is often used to increase energy levels and thinking skills. Since one cup of black tea typically contains about half as much caffeine as one cup of brewed coffee, it is often considered a low-caffeine alternative to coffee.

Black tea also contains other chemicals, called theaflavins, that may have effects in the body. These chemicals can act as antioxidants and may also be able to lessen swelling (inflammation). Some people drink black tea to improve overall health and reduce their risk of chronic conditions. But the benefits of black tea for any specific health purpose are not well defined. Some research suggests that regularly drinking black tea for a long time may improve certain health outcomes, but results vary.

Herbal products, such as black tea, naturally contain many different chemicals. The amounts of each chemical in a specific black tea product may vary. Some, none, or all of these chemicals may have effects on the body. These effects may change depending on how much of each chemical is found in the product you are using.

How should I store black tea?

You should store black tea according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of black tea?

The most common side effects of black tea are listed below. These side effects may vary depending on the specific product you are using and the amount of caffeine it contains. Tell your health care provider if you have any of these side effects that bother you.

• Increased need to pee
• Nervousness or restlessness
• Nausea or an upset stomach
• Trouble sleeping (especially if you drink black tea later in the day or close to bedtime)

There may be other side effects of black tea that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of black tea?

While less common, the most serious side effects of black tea are described below, along with what to do if they happen.

Severe Allergic Reactions. Black tea may cause allergic reactions, which can be serious. Stop drinking black tea and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Heart Effects. Black tea contains caffeine, which may increase your risk of certain heart effects, such as raising your heart rate and blood pressure or causing an abnormal heart rhythm (arrhythmia). These effects are more likely with higher doses of caffeine or with an increase in the amount of caffeine you have in a day. Black tea contains less caffeine than coffee, but caffeine is found in many other common foods and drinks as well. Keep track of all of your caffeine sources to make sure you are not getting too much.

If you measure your blood pressure and the top number (systolic) is 180 or higher or the bottom number (diastolic) is 120 or higher, get medical attention right away. Also, call your health care provider or get medical attention right away if you have chest pain, a fast or irregular heartbeat, or if you feel your heartbeat more than usual.

Precautions

Who should not use black tea?

Allergies to Ingredients. People who are allergic to any of the following should not use black tea.

• Black tea
• Caffeine
• Camellia sinensis
• Theaflavin
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific black tea products they stock.

What should I know about black tea before using it?

Black tea is a beverage. It may be available in tea bags, as loose leaf, or in powder form.

Extracts made from black tea, called black tea extracts, may be sold as dietary supplements. These products cannot be marketed to treat or cure a disease. Some black tea extracts contain dried black tea, but others may only contain certain chemicals found in black tea, such as caffeine or theaflavins. Read the product label closely to understand which ingredients and chemicals it contains.

Keep black tea out of the reach of children.

Herbal products, such as black tea, naturally contain many different chemicals. The amount of each chemical in a specific black tea product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year the leaves were harvested, and the way they were processed after harvest. If you switch to a new package or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

Black tea naturally contains caffeine. Some dietary supplements that contain black tea extracts may also contain added caffeine. However, dietary supplements and non-soda beverages are not required to state their caffeine content. Use these products with caution, especially if you are sensitive to caffeine or you regularly drink caffeinated beverages. Too much caffeine can increase your risk of side effects.

The FDA has not tested black tea extracts to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using black tea?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if black tea is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• Anxiety
• Fibrocystic breasts
• Heart rhythm problems
• Heart disease
• Kidney or liver problems
• Stomach ulcers
• Tremors

Other Medicines and Supplements.Black tea may interact with other medicines and supplements. Before taking black tea, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how black tea could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Also, tell your health care provider how much caffeine you usually get from foods, drinks, and dietary supplements.

Breastfeeding. The caffeine in black tea passes into breast milk. Large amounts of caffeine can cause fussiness or sleeping problems in breastfed babies. Tell your health care provider if you are breastfeeding or plan to breastfeed. Also, tell your health care provider how much caffeine you usually get from foods, drinks, and dietary supplements.

Interactions

Does black tea interact with foods or drinks?

There are no known interactions between black tea and foods or drinks. But black tea contains caffeine, and caffeine is found in many common foods and drinks (such as coffee, tea, soda, chocolate, and some protein bars). Keep track of all of your caffeine sources to make sure you are not getting too much. Too much caffeine can increase your risk of side effects.

Black tea contains caffeine, which has the opposite effect of alcohol. When caffeine and alcohol are used together, you may feel like neither is affecting you the way it usually does. This may lead you to drink more alcohol or have more caffeine than you otherwise would, increasing your risk of side effects.

Does black tea interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before drinking black tea.

• Fluconazole (Diflucan), itraconazole (Sporanox, Tolsura), ketoconazole, posaconazole (Noxafil), or voriconazole (Vfend), which are medicines used for fungal infections
• Cimetidine (Tagamet HB), which is a medicine used for heartburn
• A barbiturate, such as butalbital, phenobarbital, or primidone, which is a medicine that may be used to treat insomnia, migraine, or seizures
• Phenytoin (Dilantin, Phenytek, and others), which is a medicine to control seizures
• Theophylline (Elixophyllin, Theo-24), which is a medicine for asthma or certain other breathing problems
• Any product that contains caffeine, which is often found in medicines used for reducing water weight (diuretics), staying awake, easing headaches, and hangover relief

Black tea contains caffeine. Many medicines may alter the blood levels of caffeine and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

The interactions between black tea and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with black tea is incomplete. Always check with your health care provider before drinking black tea with any medicines.

Dosing

What should I do if I accidentally use too much black tea?

If you or someone else has used too much black tea, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Black tea naturally contains caffeine, which may not be listed on the label. Keep track of all of your caffeine sources to make sure you are not getting too much. Too much caffeine can increase your risk of side effects.

If you are using a supplement containing black tea extract, read the product label closely and speak to a health care provider about how to take it safely. Do not take double or extra doses, even if you miss a dose.