Using Herbal Supplements

Guido R. Zanni, PhD
Published Online: Monday, December 13, 2010

Are all product labeled "natural" safe and do they really improve symptoms? Pharmacists can answer these and other questions patients have about herbal supplements.

People often talk about the benefits of herbal supplements. They praise ginkgo for memory improvement, St. John’s wort for depression, ginseng for energy, and kava to reduce tension, to mention only a few. Do they really work?

Some do. Many people use herbal supplements without problems, and report they feel better. If you want to try herbal supplements, you should discuss it with your doctor first. Products labeled “natural” are not necessarily safe. In the wrong dose or mixed with other medicines, some herbal products can be dangerous.

What is an Herbal Supplement?
Herbal supplements come from plants or parts of plants, such as seeds or flowers. Herbal supplements are also called botanicals. Herbs are sold in many forms, including teas, oils, fresh produce, tinctures (a solution of water, alcohol, and herbs), and dried plants. Herbal supplements are products that:
• Supplement your diet (add to and not replace something);
• Contain one or more ingredients;
• Are taken by mouth in the form of tablets, capsules, or liquid; and
• Are clearly labeled as dietary supplements.

Herbal supplement manufacturers do not have to prove the safety of their products like medication manufacturers do. The Food and Drug Administration (FDA) lets them tell you what conditions their products might help—called “claims”—if they have information to prove the claim. Once a product is on the market, the FDA monitors the maker’s claims, package inserts, and any problems that consumers report. The FDA has taken legal action against a number of manufacturers for making false or deceptive claims or because the product was unsafe.

Can I Take Supplements If I Am on Medicine?
It depends. Herbal supplements may change the way your body reacts to medicine or over-the-counter products. For example, St. John’s wort reduces the body’s ability to process some medicines. This means you will get a smaller amount than what you need. If you take any of the drugs listed in Table 1, you may not be able to use some herbal supplements. This is why it is important to get your doctor’s approval before using herbal supplements. 

Table 1

Although some herbal supplements may be safe for healthy people, they can make some existing health conditions worse, even if you are not taking medicine for the condition. Some of these are listed in Table 2.

Table 2

Generally, you should not use herbal supplements if you are pregnant or breast-feeding, are having surgery within 2 weeks, taking medications, or are younger than 18 or older than 65 years of age. Keep a record of supplements you take and share it with any health care worker who asks for a list of your medicines. Learn as much as possible about the supplement you are taking, because there may be some “do’s and don’ts.” For example, kava should never be mixed with alcohol. It can cause liver damage and even death.

A good place to find information about specific herbs is the National Center for Complementary and Alternative Medicine ( herbsataglance.htm) or the National Library of Medicine ( medlineplus/herbalmedicine.html).

• Before taking herbal supplements, make sure you know the answers to these questions:
• What might the benefits be?
• When will I notice its effects? (Some supplements have immediate effects. Others take several weeks.)
• Will this supplement worsen any of my medical conditions?
• Do I understand the risks in using this supplement?
• Am I taking any medicine that might be affected by the supplement?
• What is the proper dose? (Never exceed the recommended dose.)
• Do I understand the label instructions?
• How long should I take it? (Some supplements should not be taken longterm.)

Only buy products manufactured in the United States. Scientists have found toxic ingredients and prescription drugs in herbal supplement products made in China, India, and Mexico. Avoid products claiming to diagnose, treat, prevent, or cure diseases. Manufacturers following government guidelines are not allowed to make these types of claims. It’s also important to understand possible side effects. Table 3 lists side effects for some commonly used herbal supplements.

Table 3
Additional Information

Your local pharmacist can answer any questions you might have about a particular supplement. The Internet is also a good place to find information, but it has a lot of false and misleading information as well. It’s better to search the Web sites listed in this handout. The Dietary Supplements Labels Database of the National Library of Medicine is also useful. It has information on more than 4000 brand name supplements and their safety. You can search the database by brand name or ingredients. It can be found at Once you begin using an herbal supplement, watch for special alerts and advisories that may be issued about the supplement (http://nccam.nih. gov/news/alerts/).

Final Thought

Herbal supplements are only one category of supplements. Other supplements include vitamins, antioxidants, and various products like fish oils. Similar to herbal supplements, there are risks associated with some of these products, and you should discuss their use with your doctor. PT

Dr. Zanni is a psychologist and health systems consultant based in Alexandria, Virginia.

Related Articles
Up to 15% of patients who receive a statin experience muscle pain, for which clinicians have only a few options: prescribing a different statin, reducing the dose of the current statin, or stopping statin therapy entirely.
Vitamin D deficiencies are causally associated with increased mortality rates.
Compared with a one-size-fits-all approach, personalized dietary recommendations based on an individual’s genetic makeup improve his or her eating habits.
Although most pharmacies carry a line of natural products, patients often turn to the Internet to find information on those supplements and purchase them.
Latest Issues