Herbs and Botanicals: Frequently Asked Questions

These are the questions readers ask most about herbal remedies. The answers are short and each one rests on a source we read. They are general information, not advice for one person. A pharmacist or clinician who knows your health and medicines is the right person for personal questions.

Do herbs work?

It depends on the herb, the part of the plant, the preparation and the question. NCCIH says the amount of scientific evidence on dietary supplements varies widely, with a lot of information on some and very little on others. [1] Three examples show the range:

So "herbs work" and "herbs do not work" are both too broad. Look up the specific herb and use on its own page, for example St. John's Wort and Ginkgo.

Are herbal supplements safe?

Some have documented serious risks and some have little safety information. MedlinePlus says many people believe products labeled "natural" are always safe, which is not necessarily true, and that some herbs, such as comfrey and ephedra, can cause serious harm. [5] NCCIH says supplements may interact with medicines or pose risks for people with certain medical problems or who are going to have surgery. [1] Examples from NCCIH include liver damage reported with some bioavailable curcumin products [6] and with black cohosh products. [7] See Herb Evidence and Safety at a Glance for a table, and Herb Safety Quick Reference for warning signs.

Is natural better than synthetic?

We did not read a source that compares a plant-made compound with a lab-made copy of the same compound, so on that narrow question: Proper evidence not found. What the sources we read do say is that origin does not decide safety. NCCIH notes that many dietary supplements, and some prescription drugs, come from natural sources, but "natural" does not always mean "safe." [8] NCCIH also notes the FDA approved a specific green tea extract ointment as a prescription drug, an example of a plant extract that is a prescription drug. [9] For how plant-derived medicines differ from supplements, see Herbs, Spices, Supplements and Drugs.

Does a long history of use prove an herb works?

No. Traditional use and research are two separate kinds of evidence. NCCIH says turmeric has historically been used in Chinese, Indian (including Ayurvedic), Islamic and Thai traditional medicine systems, [6] and also says we do not know enough to conclude definitively that turmeric or curcumin is beneficial for any health purpose. [6] In the EU, a traditional-use registration needs at least 30 years of use, including 15 in the EU, and does not require clinical trials if safety data and plausible efficacy are shown. [10] Respect for a tradition is not the same as a test result. See Traditional Use vs Research Evidence.

Who checks herbal products?

In the US, NCCIH says the FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed, [1] and can act against adulterated or misbranded supplements only after a product is on the market. [8] NCCIH adds that companies are responsible for having evidence that their supplements are safe. [8] The EU has routes for herbal medicines, including well-established use, which the EMA describes as at least ten years of use with recognised efficacy and an acceptable level of safety. [10] Details are in US Regulation of Herbal Supplements.

Can I take herbs with my medicines?

Do not assume you can. NCCIH says some herbs and medicines interact in harmful ways, and that St. John's wort can weaken the effects of many medicines. [2] Ginkgo may raise bleeding risk with anticoagulants such as warfarin, [4] and garlic supplements may raise bleeding risk too. [11] Never stop or change a prescribed medicine on your own. Ask the prescriber or pharmacist. See How Interactions Work.

What about surgery?

NCCIH says certain dietary supplements may increase the risk of bleeding or affect your response to anesthesia. [8] Tell the surgical team about every herb and supplement you use.

Is what is on the label what is in the bottle?

Not always. NCCIH says what is on the label may not be what is in the product, and that the FDA has found prescription drugs, including anticoagulants, in products sold as dietary supplements. [8] NCCIH also says some commercial black cohosh products contained the wrong herb. [7] A "standardized" claim does not necessarily guarantee quality or consistency. [8] See Quality Testing and Certifications.

Can an herbal supplement say it treats a disease?

In the US, NCCIH says supplement labels cannot claim to diagnose, treat, cure, mitigate or prevent any disease; those claims are only permitted for drugs. [8] A product that says it cures something is a marketing claim, not evidence.

Where do I report a problem?

NCCIH says you can report safety concerns about a dietary supplement through the US Health and Human Services Safety Reporting Portal. [8] Other countries are covered in How to Report a Side Effect in the UK, Canada, Australia and the EU.