What is herbal tea?
Regular tea (such as black, white, oolong, and green teas) are drinks made by soaking the leaves of the tea plant (called Camellia sinensis) in water. The leaves are strained out and the water is consumed.
Herbal teas are drinks made from plants (and plant parts) other than the tea plant, soaked in water. The water is consumed but the wet plants are strained out.
Common plants used in herbal tea include
- Licorice root
- Orange peel
- Cinnamon (and other spices)
- Other flowers
Herbal teas do have many benefits, and often people drink them for their medicinal properties. Many herbal teas contain antioxidants, which are lower the risk for developing chronic diseases like heart disease and cancer.
However, because they do have medicinal properties, they can often interact with prescription and over-the-counter medications.
Both regular teas and herbal teas (and other herbal supplements) contain compounds that can interact with medications. Some of these interactions enhance the action of the drug, and some of them decrease the action of the drug. Interactions between herbs (which are regulated like food) and medications are called food-drug interactions.
Why is this important?
Medications are given in specific doses based on how they are expected to act in the body. Regular and herbal teas can affect how a drug acts in the body at a certain dose.
For example, if you are taking Coumadin (or warfarin, or aspirin: anticoagulants/blood thinners to prevent blood clots) and you also are drinking chamomile tea (which can interfere with anti-clotting medications), you could end up with not enough clotting action (a little clotting ability is healthy and necessary to stop bleeding if you get a cut, etc.).
It is very important to talk with your health care provider (especially pharmacists) about all the medications and herbal supplements you consume, including regular and herbal teas. In addition, make sure you know what foods and herbs can interact with the medications you take.
Common interaction warnings
Here are a few herbs that can have the potential to interact with medications. Sources: Natural Standard and UMMC’s CAM Index (see Resources, below)
Note: This is not a complete list. You and your healthcare team are responsible for checking your medications for interactions (also see site Disclosure).
- Licorice root – Licorice should be avoided or consumed with caution if you are taking ACE inhibitors, diuretics, digoxin, aspirin, corticosteroids, insulin, oral contraceptives, or laxatives. These recommendations are based on animal and human studies, case studies, and expert opinion based on the known effects of licorice.
- Peppermint – One of the most commonly reported side effects of peppermint is that it causes heartburn. Peppermint can relax the lower esophageal sphincter (the par t of the body that keeps food from going out of the stomach back up into your esophagus, which is the tube the food goes down), especially in people with gastroesophageal reflux disease (GERD), despite medications to prevent this from happening.
- Ginger – The common warning for ginger is to avoid when taking anticoagulants, based on animal studies and human case studies, where ginger has been shown to have similar properties. Taking both ginger and anticoagulant drugs may cause too much bleeding; however, scientific evidence is limited
- Chamomile – The usual warning for chamomile is to avoid taking it with sedatives (including alcohol) and anticoagulant medication, based on animal and human studies, because of evidence that it can increase drowsiness and may interact with blood clotting. Chamomile also may have some effect on certain drugs like oral contraceptives and statins that are broken down in the liver, based on in vitro studies.
Here are some resources to find out if you may have a potential interaction.
Note: This is not a complete list. You and your healthcare team are responsible for checking your own medications, using resources not limited to those mentioned here.
- Pharmacist and integrative pharmacist
- Food-drug interaction books (see one example*) - list drugs and the interactions they can have with foods and herbal supplements
- Natural Standard – evidence-based resource that reviews complementary and alternative medicines and their uses, compares to effectiveness; some information is only available to subscribers, but you may have access through your local or university libraries
- Complementary and Alternative Medicine Index from U of Maryland Medical Center – includes descriptions of treatments, side effects, and interactions
- “When Foods and Drugs Collide — Studies Expose Interactions Between Certain Foods and Medications” interesting article, at the very bottom it has a table of potential food-drug interactions
Note: Regular and herbal teas can also be harmful in certain medical conditions including pregnancy, and you should talk with your healthcare provider and Registered Dietitian if you have any existing medical condition.
*Disclaimer: The food-drug interaction book link is an affiliate link. This means, at no extra cost to you, you will be supporting me and this blog by buying the book or anything else on Amazon.com for 24 hours after using my link. I only use affiliate links to things I believe are worth recommending. This was a textbook I used in my nutrition classes, at the undergraduate and graduate levels. (If you don’t want to support me in this way and you’ve already clicked my affiliate link, clear your browser’s cookies before making a purchase on Amazon, or wait for the 24 hours to end).
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