Dec 06

5 Herbs That May Harm Your Liver

Herb that can harm the liverHerbal remedies can be effective, safe, and less expensive alternatives to conventional medicines, depending on what you want to treat. These are just a few of the reasons why more and more people are embracing the use of herbs for common and even not-so-common symptoms and ailments. But just because herbal remedies are natural doesn’t mean they are always safe.

After all, herbs can be powerful medicine, and as a result, they frequently possess components and properties that may cause adverse reactions or effects if used improperly. That brings me to the topic of herbs that can harm your liver.

The liver is a major filtering system that processes your blood and detoxifies toxic substances. One of the reasons why people are warned about taking too much of the common OTC drug acetaminophen (Tylenol), for example, is that it can cause liver damage. Many other examples of liver damage associated with improper (and even proper) drug use exist.

Something similar can happen with herbal remedies.

Although the majority of herbal remedies are safe when taken properly–that is, at the right dosages, for the correct length of time, and for the correct reason—several plants should be eyed with caution.

5 herbs that may harm your liver


As a resident of the Sonoran desert in the southwest, I often enjoy the aroma of the creosote bush (aka, greasewood) after a rain. The leaves of the bush are known as chaparral (Larrea tridentate), a high-antioxidant herbal remedy that has been used to treat painful skin conditions, bronchitis, cancer, and AIDS. The problem with chaparral, however, it that your bile ducts can become blocked if you take the herb for about three weeks. Even though chaparral supplements have not been banned, it may be a good idea to look elsewhere for a remedy for bronchitis or skin conditions.

The good news is that this problem typically goes away once you stop taking the herb, but the not-so-good news is that severe liver damage can still be the result in some patients. Talk to your healthcare provider before using any chaparral teas, salves, or tablets.


This herb has a comforting name, and in fact it has a tradition of use for soothing an upset stomach when used as a tea and to treat skin conditions when applied topically. However, comfrey (Symphytum officinale) contains pyrrolizidine alkaloids, which are toxic to the liver and can be deadly. That’s why comfrey is no longer available in any oral form in the US, UK, Germany, Canada, and Germany.

For treating skin inflammation, sprains, strains, osteoarthritis, and pulled muscles, you can try topical products containing comfrey. The healing substances in the leaves and roots include allantoin, tannins, and rosmarinic acid. However, your skin can still absorb the toxic alkaloids, so it is recommended you limit your use of comfrey topicals to 10 days per treatment period and no more than six weeks per year. Never use comfrey on broken skin.

herbs that can harm your liverGermander

Approximately 250 species of plants in the mint family fall under this umbrella term, but among the more popular species is Teucrium chamaedrys. The flowers of this germander has been used for millennia for diabetes, obesity, heartburn, gout, and high blood pressure. Cases of acute and chronic hepatitis have been documented after individuals took the herb for two months at recommended doses. Symptoms (e.g., jaundice, nausea, abdominal pain) usually go away after stopping the remedy, but liver damage may persist.

Other species of Teucrium (e.g., T. polium, T. capitatum, T. viscidum) also have been involved in liver problems, so beware when you read supplement labels, especially those marketed for weight loss. Since people who are trying to lose weight typically take weight loss supplements for an extended period of time, those that contain species of germander could cause liver problems.

Green tea extract

If you’re a green tea lover like me, you may be taken aback by its presence on this list. However, we are talking about how green tea extract may be damaging to the liver when used in a specific way; that is, when fasting. That’s because the liver can become overwhelmed by the potent antioxidants in green tea extract if you are fasting or going through a cleansing program. More specifically, experts believe the catechins and their gallic acid esters, especially epigallocatechin-3-gallate, can promote the formation of potent cell-damaging factors called reactive oxygen species.

According to Dr. Rubman, the compounds in green tea that are super for people who have a normal metabolism “can harm someone whose metabolism is not working at its best.” Therefore, green tea extract is normally safe for your liver if you take it between meals and not when you are fasting.


Although the traditional use of kava (Piper methysticum) has been as a mild intoxicant, it has gained a popular hold in Western medicine for managing insomnia and anxiety. This Pacific island native came under scrutiny when researchers found an association between its use and liver failure, hepatitis, and other liver problems. Therefore some European countries have restricted or banned its use, although it is still available in the United States.

Results of the first-ever placebo-controlled, double-blind trial of kava in people with generalized anxiety disorder were reported in 2013. The researchers noted a significant reduction in symptoms among those who took kava during the six-week study and no accompanying liver issues.

Despite numerous research efforts, however, it’s still not certain whether kava alone is responsible for liver damage or only when it is combined with other herbs or drugs. Naturopathic physician Andrew L. Rubman, ND, founder and medical director of the Southbury Clinic for Traditional Medicine in Southbury, Connecticut has suggested that kava may be safe when extracts of the entire plant are used but that it may be hazardous if an isolated chemical from the plant is used in supplements. Kava seems to be an herbal remedy that you should discuss with a professional before using it.

Herbal remedies can be powerful medicine, so it’s critical that you understand which options may pose a health risk for your liver. The five herbs discussed here are not the only ones that can compromise the health of your liver, so consult a naturopath or other knowledgeable professional before you take any herbal remedies. Also be sure to reveal any medications or supplements you are taking.

ALSO READ: Herbs For Your Heart

Fenugreek, More Than an Odd Name


Bottomline Health. The truth about herbal supplements and your liver

Bunchorntavakul C, Reddy KR. Review article: herbal and dietary supplement hepatotoxicity. Alimentary Pharmacology and Therapeutics 2013 Jan; 37(1): 3-17

Sarris J et al. Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study. Journal of Clinical Psychopharmacology 2013 Oct; 33(5): 643-48

University of Maryland Medical Center. Comfrey

University of Maryland Medical Center. Kava.


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