What “Herbal Safety” Actually Means
An herbal supplement is a product made from a plant, algae, or fungus. It is sold as a tea, capsule, tablet, powder, or extract. Unlike a prescription drug, an herbal supplement does not need proof of safety or effectiveness before sale. It may be sold without proof. Under federal rules, the company selling it is responsible for that evidence, and the U.S. Food and Drug Administration (FDA) generally reviews a product only after it is already on shelves. That single fact explains why herbal safety is really a set of questions. You ask before combining an herb with a prescription, an upcoming operation, or pregnancy. It is not a label you can trust at face value.
This guide translates two National Institutes of Health resources — Using Dietary Supplements Wisely and Herbs at a Glance, both from the National Center for Complementary and Integrative Health (NCCIH) — into a checklist and worksheet you can bring to an actual conversation with a pharmacist, surgeon, or prescriber.
Myth Versus Reality
- Myth: “Herbal” and “natural” mean an ingredient is automatically gentle and safe.
- Reality: NCCIH notes that natural sources do not always mean safety — kava, for example, is a plant in the pepper family, but kava supplements have been linked to liver disease.
- Myth: If a supplement is sold in stores, the FDA has already confirmed it works and is safe.
- Reality: Outside of a narrow rule for new ingredients, the FDA is not authorized to review a dietary supplement for safety or effectiveness before it is marketed. The agency can act only after a problem is reported.
- Myth: A label that says “standardized,” “verified,” or “certified” guarantees consistent quality.
- Reality: NCCIH states that those terms do not necessarily guarantee product quality or consistency from batch to batch.
- Myth: Herbal products can't interfere with prescription medicine because they're “just plants.”
- Reality: Herb-drug interactions are well documented. St. John's wort is a commonly cited example — NCCIH notes it can make many medications less effective.
- Myth: It's fine to keep taking herbal supplements right up until a scheduled surgery.
- Reality: Certain dietary supplements can raise the risk of bleeding or change how the body responds to anesthesia, so NCCIH advises telling every health care provider involved, as far ahead of the operation as possible.
- Myth: A supplement is automatically fine during pregnancy or while nursing because it's herbal.
- Reality: Many dietary supplements have not been tested in pregnant women, nursing mothers, or children, so their effects in those situations are often unknown rather than confirmed safe.
Where the Evidence Is Strong — and Where It Runs Out
Evidence quality varies enormously from one herb to the next, and even within a single herb's research base. A few limits worth knowing before you read any single study or headline:
- Some supplements have real evidence behind a specific, narrow use — NCCIH points to melatonin for jet lag as an example — while others, like ginkgo for dementia, have been tested and not shown a benefit.
- Research on the same ingredient can conflict. Glucosamine and chondroitin for osteoarthritis symptoms is one example NCCIH flags as having mixed results across studies.
- What's tested in a study is not always what's in the bottle you buy. The FDA has found prescription drug ingredients — including blood thinners and anti-seizure medications — hidden in products sold as dietary supplements.
- Traditional or historical use of an herb is a record of how people have used it, not a substitute for clinical testing of safety or effectiveness.
- Rare but serious harms exist: NCCIH cites a 2015 study estimating roughly 23,000 emergency room visits a year in the U.S. tied to dietary supplements, along with growing reports of acute liver injury tied to some products.
None of this means every herbal product is risky, or that the traditional systems these ingredients come from lack value — it means the specific claim, the specific product, and your specific situation all need to be checked separately rather than assumed.
Before You Combine an Herb With a Medicine
Interactions can change how well a medicine works or how strongly it acts in your body. Questions worth bringing to a pharmacist or prescriber:
- Does this herb have any documented interaction with the specific medicine I take — not just its general drug class?
- Could this herb make my medicine less effective, more potent, or change how quickly my body clears it?
- Is there a known concern with this herb and any medical condition I already have?
- Where can I look up this specific herb — for example, NCCIH's Herbs at a Glance fact sheets — before I start taking it?
- If I notice a new symptom after starting the herb, at what point do I stop it and call my provider?
Before Surgery
NCCIH's core safety guidance here is direct: certain dietary supplements may increase the risk of bleeding or affect your response to anesthesia. Bring these questions to your surgical team as early as possible — ideally at the pre-operative appointment, not the morning of the procedure:
- Have I told my surgeon and anesthesiologist about every supplement I take, including ones I consider minor, like a daily tea or tincture?
- How many days or weeks before surgery does this specific supplement need to be stopped?
- Are there any supplements I'm taking that are specifically linked to bleeding risk or anesthesia interactions?
- When is it safe to restart the supplement after the procedure?
Before or During Pregnancy and Nursing
Because many dietary supplements have not been tested in pregnant women, nursing mothers, or children, the honest starting position for most herbal products in this situation is “untested,” not “unsafe” or “safe.” Questions to bring to an obstetric provider or midwife:
- Has this specific herb been studied at all in pregnancy or while nursing — or is it simply untested?
- Are there ingredients in this product besides the named herb that I should also ask about?
- Is there a lower-risk, better-studied alternative for the specific concern I'm trying to address?
- If I already started taking something before I knew I was pregnant, who should I tell, and how soon?
A Simple Conversation Worksheet
Before any appointment involving new medicine, a surgery date, or a pregnancy update, write down:
- The exact name of every herbal supplement you take, including the brand, and a photo of the label if possible.
- The dose and how often you take it.
- How long you've been taking it and why you started.
- Any side effect, however minor, you've noticed since starting it.
- Every prescription and over-the-counter medicine you're currently taking, so your provider can check the full list against the herb — not the herb in isolation.
Bring that list to every provider involved in your care, not just one. NCCIH's guidance is consistent on this point: talk with your health care providers about any complementary approaches you use, so decisions are shared and well-informed rather than made by one specialist without the full picture.
Red Flags That Warrant Immediate Medical Attention
Stop the supplement and contact a health care provider promptly — or seek emergency care — if you notice:
- Yellowing of the skin or eyes, dark urine, or unusual fatigue, which can signal liver injury.
- Unusual or excessive bleeding or bruising.
- Chest pain, a racing heartbeat, or difficulty breathing.
- Difficulty swallowing a large vitamin or supplement pill, which NCCIH notes is a documented cause of emergency visits among older adults.
For a medical emergency, contact local emergency services right away rather than waiting to research the product first.
Where This Guide Ends and Professional Advice Begins
This article explains general patterns documented by NCCIH — it does not evaluate any specific brand, tell you whether to start or stop a particular product, or replace a conversation with a pharmacist, surgeon, or prescriber who knows your medical history. Herbal traditions carry real cultural and historical depth, and that context is worth respecting; it simply isn't a substitute for checking a specific product against your specific medicines, procedure, or pregnancy.
For background on how we source and verify articles like this one, see our Editorial Policy. To learn more about NewEasternHealth.com's independent, non-clinical role, visit our About page.
By NewEasternHealth.com Research Team. Updated September 2026. This article is for general educational purposes only and is not medical advice. NewEasternHealth.com is an independent consumer wellness publication; we are not a medical practice and do not employ licensed clinicians. Always talk with a qualified health care provider before starting, stopping, or combining any dietary or herbal supplement, especially if you take medication, are scheduled for surgery, or are pregnant or nursing.