Cancer Home > Is Green Tea Safe?
Green tea products claim to have numerous health benefits, but is green tea safe? Since green tea contains caffeine, it could worsen anxiety disorders, heart conditions, high blood pressure, and glaucoma. There have also been some cases of liver damage possibly due to green tea supplements (not the beverage). Before taking green tea products, let your healthcare provider know if you are pregnant or breastfeeding.
- High blood pressure (hypertension)
- Iron deficiency anemia
- Liver disease, such as liver failure, cirrhosis of the liver, or hepatitis
- Any heart problems
- Any allergies, including allergies to foods, dyes, or preservatives.
- Pregnant or thinking of becoming pregnant
- As dietary supplements, green tea supplements (such as green tea capsules or tablets) are not closely regulated. They can be marketed without any proof that they are either safe or effective. Do not assume that just because a product is sold in the United States that it is safe or effective. Be sure to look for green tea supplements from a reputable manufacturer. Your pharmacist is a good resource for information about which manufacturers are most reputable.
- Green tea contains caffeine, which may make anxiety disorders worse. If you notice increased anxiety while taking green tea, it is probably a good idea to avoid green tea products.
- The caffeine in green tea can worsen some heart conditions. If you have any heart problems, do not take green tea supplements (or drink significant amounts of green tea) without checking with your healthcare provider.
- There have been a few cases of liver damage possibly due to green tea. Generally, these cases involved green tea supplements (not green tea as a beverage). It is not known how or why green tea might cause liver damage. If you have liver disease, you should check with your healthcare provider before taking green tea supplements.
- If you have glaucoma, do not take green tea supplements (or drink significant amounts of green tea) without checking with your healthcare provider. The caffeine in green tea can make glaucoma worse.
- If you have high blood pressure, green tea may increase your blood pressure even more (due to the caffeine content). However, this is not a problem for everyone, especially people who are accustomed to consuming caffeine on a regular basis.
- Green tea can interact with some medications (see Green Tea Drug Interactions for more information).
- Green tea contains caffeine. If you choose to avoid caffeine during pregnancy or while breastfeeding, you should also avoid green tea, unless it has been decaffeinated. It is not known whether green tea is safe for pregnant or breastfeeding women (see Green Tea and Pregnancy and Green Tea and Breastfeeding).