Herbal Products and Supplements


Are herbal health products and supplements safe because they’re natural?

Not necessarily. Don’t think that all herbal health products and supplements are safer than medicines just because they occur in nature or come from plants. Although herbal products and supplements are advertised as “natural,” they aren’t necessarily natural to the human body.

Some herbal products and supplements might contain other ingredients that could make you sick. Sometimes they contain drugs that aren’t listed on the label, such as steroids or estrogens. Some of these products may even contain toxic (poisonous) substances, such as arsenic, mercury, lead, and pesticides.

However, some manufacturers of vitamins, minerals, and dietary supplements follow the U.S. Pharmacopeial (USP) Convention quality standards. These supplement manufacturers volunteer to have their supplements tested for quality and purity by an outside company before they are sold.

These supplements often display additional quality credentials on their labels, such as “USP Verified” or “ConsumerLab.com Approved Quality.”

Choose your supplements carefully, and talk to your family doctor and/or your pharmacist if you have questions.

USP Seal

What types of herbal products and supplements are available?

Hundreds of herbal products and supplements are available. They are advertised to treat just about any symptom. However, there isn’t a lot of trustworthy evidence to support the vast majority of these advertising claims.

Some of the most popular herbal products and supplements include chondroitin sulfate, echinacea, garlic, ginkgo biloba, ginseng, glucosamine, kava, melatonin, phytoestrogens (such as black cohosh, dong quai, and soy), saw palmetto, and St. John’s wort.

How do I safely take herbal products and supplements?

Read the directions on the supplement label to learn how much to take and how often to take it. If you have any questions about how much to take, call your family doctor or pharmacist.

Follow these tips to make sure you are taking the right amount:

  • If you are taking a prescription medicine, ask your doctor if it’s okay to also take herbal products and supplements.
  • Take only the amount recommended on the label. Don’t assume that more of an herbal product or supplement will work better or quicker. Taking more than the recommended amount can be dangerous.

How can I safely store herbal products and supplements?

Store all supplements up and away, out of reach and sight of young children. Keeping  these products in a cool, dry place will help prevent them from becoming less effective before their expiration dates. Do not store them in bathrooms or bathroom cabinets, which are often hot and humid.

Is it safe to take herbal products if I have health problems?

Herbal products and supplements may not be safe if you have certain health problems. Older adults also may be at increased risk of problems from these products. Talk to your doctor before taking herbal products if you have any of the following health problems:

  • Blood clotting problems
  • Cancer
  • Diabetes
  • Enlarged prostate gland
  • Epilepsy
  • Glaucoma
  • Heart disease
  • High blood pressure
  • Immune system problems
  • Parkinson’s disease
  • Psychiatric problems
  • Liver problems
  • Stroke
  • Thyroid problems

If you are going to have surgery, be sure to tell your doctor if you use herbal products. Herbal products can cause problems with surgery, including bleeding and problems with anesthesia. Stop using herbal products at least 2 weeks before surgery, or sooner if your doctor recommends it.

Can herbal health products or supplements change the way prescription or OTC drugs work?

Yes. Herbal health products or supplements can affect the way the body processes drugs. When this happens, your medicine may not work the way it should. For example, St. John’s wort reduces the amount of certain drugs absorbed by the body. This may mean the drugs aren’t absorbed at high enough levels to help the conditions for which they are prescribed. This can cause serious problems.

You should be especially cautious about using herbal health products or supplements if you take a drug in one of the following categories:

  • Drugs to treat depression, anxiety or other psychiatric problems
  • Anti-seizure drugs
  • Blood thinners
  • Blood pressure medicine
  • Heart medicine
  • Drugs to treat diabetes
  • Cancer drugs

If you take any of these drugs, talk to your doctor before taking any type of herbal product or supplement.

Can herbal health products and supplements cause other problems?

Yes. Herbal products and supplements may have other effects that aren’t listed in the box above. A few examples include the following:

  • Glucosamine products may contain sodium. If you’re on a low-sodium diet, talk to your doctor before taking glucosamine.
  • Don’t drink alcohol if you take kava products. Kava can increase the effects of alcohol.
  • The phytoestrogen black cohosh contains salicylates, so avoid it if you are sensitive to aspirin or other salicylates.

Also, you shouldn’t take more than the recommended dose of any herbal health product or supplement. The problems that these products can cause are much more likely to occur if you take too much or take them for too long.

Funding and support for this material have been provided by the Consumer Healthcare Products Association.


Written by familydoctor.org editorial staff

Reviewed/Updated: 10/13
Created: 09/05