What are other names for this remedy?
Type of medicine: natural remedy
Scientific and common names: Camellia sinensis, Thea bohea, Thea sinensis, Thea viridis, green tea, Chinese tea, Japanese tea, green tea extract
What is green tea?
Green tea comes from a large shrub with evergreen leaves. The shrub is native to eastern Asia. It has leathery, dark green leaves and fragrant, white flowers. The dried, cured leaves have been used to prepare brewed drinks for more than 4000 years.
Green tea and black tea come from the same plant, but green tea leaves are not fermented Green tea has many of the same chemicals as the fresh leaf.
What is it used for?
This remedy has been used to treat several conditions. Studies in humans or animals have not proved that this remedy is safe or effective for all uses. Before using this remedy for a serious condition, you should talk with your healthcare provider.
This remedy is helpful to treat genital wars and high cholesterol.
Green tea has been taken by mouth to treat:
- Edema (fluid retention)
- Gum disease
- Help prevent dental cavities and treat gingivitis
- Low blood pressure
- Menopause symptoms
- Problems with thinking and concentration
Green tea bags have been used on the skin to soothe sunburn and prevent skin damage, as a compress for headache or tired eyes, and to stop the bleeding of tooth sockets.
This remedy does not appear to help treat or prevent diabetes or obesity.
The US Food and Drug Administration (FDA) does not approve uses for natural remedies. The FDA does not inspect or regulate natural remedies the way they do prescription medicines.
How is it taken?
Most green tea products can be prepared as a tea for drinking. Tablets, capsules, and liquid forms are also available. Follow the directions printed on the product label.
What if I overdose?
Symptoms of an acute overdose have not been reported.
What should I watch out for?
Talk with your healthcare provider before taking this remedy if you have:
- Panic or anxiety disorder
- Heart disease or an irregular heartbeat
- Peptic ulcer disease or colitis
- Trouble sleeping
Do not drink a lot of coffee, or cola while you are taking this remedy. These drinks also contain caffeine, and the combination may overstimulate you and cause side effects. Too much caffeine could cause side effects such as nervousness, dizziness, irritability, headaches, trouble sleeping, a need to urinate more often, and a fast heartbeat. Also check the labels of all nonprescription and prescription medicines you take. Other medicines that contain caffeine may also cause problems. Ask your healthcare provider or pharmacist if you have any questions.
If you feel dizzy or have a fast heartbeat, stop taking the green tea. If the dizziness or fast heartbeat continues, contact your healthcare provider.
If you need emergency care, surgery, or dental work, tell the healthcare provider or dentist you are taking this medicine.
Talk to your healthcare provider or pharmacist about any natural remedy that you are using or thinking about using. If your provider does not tell you how to take it, follow the directions that come with the package. Do not take more or take it longer than recommended. Ask about anything you do not understand. Remember:
- Natural remedies are not always safe.
- You should not take them if you are pregnant or breast-feeding without your healthcare provider's approval. They should not be taken by infants, children, or older adults without your provider's approval.
- They affect your body and may interact with prescription medicines that you take.
- Natural remedies are not standardized and may have different strengths and effects. They may be contaminated.
What are the possible side effects?
Along with its desirable effects, this remedy may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the remedy. Tell your healthcare provider if you have any side effects that continue or get worse.
Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help.): Allergic reaction (hives; itching; rash; trouble breathing; chest pain or tightness in your chest; swelling of your lips, tongue, and throat).
Other: nausea, vomiting, heartburn, loss of appetite, diarrhea, constipation.
What products might interact with this remedy?
When you take this remedy with other medicines, it can change the way the remedy or the medicines work. Vitamins and certain foods may also interact. Using these products together might cause harmful side effects. Before taking this remedy, talk to your healthcare provider if you are taking:
- Antiseizure medicines such as carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), and primidone (Mysoline)
- Appetite suppressants (diet pills) or other stimulant medicines such as amphetamines (Desoxyn, Dexedrine), dextroamphetamines (Adderall, Adderall XR), methylphenidate (Ritalin), and pemoline
- Bronchodilators such as aminophylline, dyphylline (Dilex, Lufyllin), and theophylline
- Cimetidine (Tagamet)
- Ciprofloxacin (Cipro)
- Clozapine (Clozaril)
- Diabetes medicines such as glipizide (Glucotrol, Glucotrol XL), glyburide (DiaBeta, Glynase PresTab), insulin, metformin (Glucophage), pioglitazone (Actos), repaglinide (Prandin), and rosiglitazone (Avandia)
- Drinks and foods containing caffeine such as coffee, tea, colas, and chocolate
- Folic acid
- Iron supplements
- Lithium (Lithobid)
- MAO inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam), and tranylcypromine (Parnate) (Do not take this medicine and an MAO inhibitor within 14 days of each other.)
- Medicines for colds, sinus problems, hay fever or other allergies that contain pseudoephedrine (including nose drops or sprays)
- Medicines to treat anxiety such as clorazepate (Tranxene), diazepam (Valium), lorazepam (Ativan), and oxazepam
- Mexiletine (Mexitil, Novo-Mexiletine)
- Natural remedies such as bitter orange, borage oil, chaparral, ephedra, ma huang, guarana, mate, and uva ursi
- Verapamil (Calan, Isoptin, Verelan)
If you are not sure if your medicines might interact, ask your pharmacist or healthcare provider. Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.
Keep all natural remedies and medicines out of the reach of children.
This advisory includes select information only. The information was obtained from scientific journals, study reports, and other documents. The author and publisher make no warranty, expressed or implied, as to the information. The advisory may not include all side effects associated with a remedy or interactions with other medicines. Nothing herein shall constitute a recommendation for the use of any remedy. Ask your healthcare provider or pharmacist for more information.
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