Herbal Medicine vs Conventional Medicine: What Is Different and What Is Not
How herbal products and conventional medicines differ in testing, regulation and labeling, what they share, and why telling your pharmacist about both matters.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read herb safety and interactions before you use anything on this page.
Herbal medicine and conventional medicine are not opposites, and neither is automatically "safer". The main documented differences are in how products are tested, regulated and labeled. The main thing they share is that both can have real effects, including side effects and interactions. If you take prescription medicines, tell the prescriber or pharmacist about any herb you use, and never stop or change a prescribed medicine without asking them.
How the sources define the terms
- Herbal medicines. WHO describes them as herbs, herbal materials, herbal preparations and finished herbal products. [1]
- Traditional medicine. WHO describes knowledge and practices that are distinct from and pre-date biomedicine, evolving with science for current use from an experience-based origin. It emphasizes nature-based remedies and holistic, personalized approaches. [1]
- Complementary medicine. WHO describes practices that are not part of a country's mainstream medicine. [1]
- Integrative medicine. WHO describes an evidence-based approach that combines biomedical knowledge with traditional or complementary knowledge. [1]
Traditional systems have their own ideas about health. They are described here in their own terms on the Therapies & Traditions pages, and the questions below are only about herbal products and how their evidence and rules compare with those for conventional drugs.
What is documented as different
| Question | Herbal products sold in the US | Prescription and over-the-counter drugs |
|---|---|---|
| Review before sale | The FDA is not authorized to review dietary supplements for safety and effectiveness before they are marketed. [2] | Companies must show the FDA evidence that these drugs are safe and effective before marketing. [2] |
| Testing | MedlinePlus says herbal medicines do not have to go through the testing that drugs do. [3] | Drugs go through that testing. [3] |
| Manufacturing and distribution rules | Less strict than for drugs. [2] | Stricter. [2] |
| Disease claims on labels | Labels cannot claim to diagnose, treat, cure, mitigate or prevent any disease. A product sold as a supplement but represented for treating a specific disease meets the definition of a drug. [2][4] | Disease claims are allowed for drugs. [2] |
| Match between label and bottle | What is listed on a supplement label may not be what is in the product. The FDA has found prescription drugs, including warfarin, in products sold as dietary supplements. [2] | Not described in the sources we read. |
| Match with studies | Supplements you buy may differ in important ways from products tested in studies. [2] | Not described in the sources we read. |
In England, the NHS says herbal medicines are not tested in the same way as standard medicines to see how well they work, and that herbal medicines are not available on the NHS. [5]
Regulation differs by country. See Herbs, Spices, Teas, Supplements and Drugs for how US, Canadian and European categories work.
What is the same
Plants are a source of conventional drugs. A review of drugs approved from 1981 to 2019 found that natural products, or synthetic variations using their structures, remain important in drug discovery, and described the anti-infective area as dependent on natural products and their structures. [6] This is a statement about natural products in general. It does not mean that a whole herb or herbal supplement works like the drug developed from a compound.Both can cause harm. "Natural" does not mean safe. MedlinePlus names comfrey and ephedra as herbs that can cause serious harm. [3] NCCIH notes that the kava plant is a member of the pepper family but kava supplements can cause liver disease. [2]
Both can interact with other medicines. NCCIH says St. John's wort can interact in dangerous, sometimes life-threatening ways with a variety of medicines. [7] The NHS lists statins, antidepressants, diabetes medicines such as metformin, blood pressure medicines such as ramipril, blood thinners such as warfarin and hormonal contraception among medicines that may not mix well with herbal medicines. [5] Details are in the medicine interactions guide.
Evidence head-to-head
Proper evidence not found for the broad question "does herbal medicine work better or worse than conventional medicine?". We looked at the NCCIH, MedlinePlus, NHS, WHO and FDA pages cited here and found no source that compares the two as whole categories. Comparisons are only meaningful for one herb, one preparation, one condition and one outcome at a time. Our side-by-side comparisons take them one question at a time, for example St. John's wort vs prescription antidepressants.Limits
Neither approach is complete on its own. Herbal products often have thin or mixed human research, and the amount of evidence varies widely from one supplement to the next. [2] Conventional drugs are not free of side effects. Use reliable sources and a pharmacist, not marketing, to decide.Frequently asked questions
Is herbal medicine less regulated than conventional medicine?
In the US, yes in the ways described above: the FDA is not authorized to review dietary supplements for safety and effectiveness before marketing, whereas drug companies must show evidence first. [2] Other countries use other systems. See the page on herbs, spices, supplements and drugs.
Are herbal medicines safer because they are natural?
Not necessarily. MedlinePlus says this belief is not necessarily true, and some herbs can cause serious harm or interact with medicines. [3]
Can I take an herb with my prescription medicine?
That depends on the herb and the medicine. Ask your pharmacist before combining them. [5] Do not stop a prescribed medicine on your own; ask the prescriber or pharmacist.
Are conventional drugs made from plants?
Some are. A review of drugs approved from 1981 to 2019 documents the continuing role of natural products and their structures in drug discovery. [6] A drug made from one purified compound is a different product from the whole plant.
Should I tell my doctor about herbs and supplements?
Yes. NCCIH says to talk with your health care providers about any complementary health approaches you use. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety: who should ask a clinician first
The FDA advises talking to your doctor, pharmacist or other health care professional before deciding to purchase or use a dietary supplement. [4] The NHS advises checking with a pharmacist first if you already take other medicine, including medicines you can buy without a prescription. [5] See talking with a health professional for what to bring.
References
- World Health Organization. Traditional, Complementary and Integrative Medicine. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Using Dietary Supplements Wisely. Page last updated January 2019.
- MedlinePlus (U.S. National Library of Medicine). Herbal Medicine. Read 2026-10-22.
- U.S. Food and Drug Administration. Questions and Answers on Dietary Supplements. Read 2026-10-22.
- NHS (England). Herbal medicines and complementary therapies. Page last reviewed 1 May 2026.
- Newman DJ, Cragg GM. Natural Products as Sources of New Drugs over the Nearly Four Decades from 01/1981 to 09/2019. J Nat Prod. 2020;83(3):770-803.
- National Center for Complementary and Integrative Health (NIH). St. John’s Wort. Page last updated May 2025.