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Herbal Medicine-Be Smart and Beware

herbalHerbal medicine is the use of leaves, flowers, stems, seeds, fruits, bark, berries, and roots of plants to prevent, relieve, and treat acute and chronic illnesses and to maintain health. While many herbs and plants seem to be safe and helpful, others can have toxic, even deadly, effects.

Indications: According to the American Botanical Council, one-third of all adults in the United States use herb and plant products in search of cheaper, gentler, natural choices to mainstream medicine.

Herbal cures are big business with billions of dollars spent each year. Herb and plant use to obtain good health are no longer confined to the realm of folklore. For example, an adult woman may take Kava Kava to help calm job stress and Echinacea when she feels a cold coming on.

Use: Herbs and plants have active properties similar to regulated drugs.

When using herb and plant treatments, knowledge is the key. Just because something is considered natural, grown in nature, does not mean that it is good to use.

The federal government classifies these products as dietary supplements as defined under the Dietary Supplement Health and Education Act and are not regulated by the Food and Drug Administration (FDA).

These products do not undergo the strict testing demanded by the FDA for other prescription and over-the-counter drugs. Manufacturers are not required to provide detailed information about their product's contents, side effects, safety, or effectiveness. They need only to provide reasonable guarantee that their product contains no harmful ingredients. Additionally, products are subject to few controls on quality and purity.

They cannot make medical claims for the product unless they have FDA approval, but they can make claims about the product's benefits without supporting proof. The preparation Ginkgo may be sold to make an individual's memory better but not to treat dementia or Echinacea can be labeled as an immune booster but not a cold remedy.

Complications:Consumers need to read about the product that they wish to use before taking it. They should be aware the only requirements on herb/plant labels are the product name, the amount of the product (for which no standards exist), and any appropriate warnings.pills

Very young and old consumers, whose metabolism may be altered through disease and individuals who have allergic responses can have a dramatic response to the products. An allergic reaction can happen with a first exposure or after you have taken the product several times. Symptoms of an allergic reaction can include rash, swelling, itching, and/or difficult breathing. If you think you are having an allergic reaction, call your doctor/healthcare provider and/or go to the nearest emergency room and/or call the emergency medical service for help.

All users need to be aware that herbs/plants have active compounds just as prescription and over-the-counter drugs do and should be cautious about herb-drug-food interactions.

Most current research on herbs used as drugs has been done in other countries. Drug and herbal companies in America are just beginning to work together to adopt standards to achieve greater agreement in product quality.

Consumers of herbs and plants need to be smart and beware that while these products can help; they can also cause harm.

For any questions about their use, a qualified herbalist or healthcare professional needs to be consulted. As an example, the following popular medicinal herbs and plants can be useful, but they also can cause complication(s).

Herb-Medication Interactions Table

-The combination of some herbal supplements and medications could have serious side effects.
-The following table may provide information on the interactions of some common herbal products.
-Please discuss with your doctor /healthcare provider any herbs you are taking, or plan on taking, for further questions/explanations of possible side effects.
-Be cautious of foods and beverages that contain herbs (example: Snapple's Moon Tea, Arizona's Memory Elixir, etc). Read food labels carefully!

Herb Medication Possible Effects/Interactions

Dong Quai

Blood-thinning drugs/Anticoagulants (Coumadin® & Heparin) & (Trental®)

Increased risk of bleeding.



Immunosuppressant drugs Tacrolimas (Prograf®), Cyclosporin (Sandimmune®; Neoral®), Azathioprine (Imuran®), Basiliximab (Simulect®), Corticosteroids (Prednisone, Decadron®), Daclizumab (Zenapax®), Muromonab (Orthoclone® OKT3®), Mycophenolate (Cellcept®)

May lower the effect of the drug.


Fever Few

Non-narcotic anti-inflammatory/pain drugs (Ibuprofen, Naproxen, etc.)

Injury to organs. 1

Blood-thinning drugs/Anticoagulants (Coumadin®, Aspirin, Heparin, Streptokinase, Urokinase, Ticlid®)

Change in blood clotting.



Blood-thinning drugs/Anticoagulants (Coumadin®, Heparin, Aspirin, Trental®)

Increased risk of bleeding.


Ginkgo or high-dose Vitamin E

Increased risk of bleeding 1


Blood-thinning drugs /Anticoagulants (Coumadin®, Aggrastat®, Ticlid®, Anturane®, Persantine®, Dicumarol®, Plavix®, Reopro®, Agrylin®, Miradon®)

May cause excessive bleeding.


Anticonvulsants/Seizure Medications (Carbatrol®, Epitol®, Tegretol®, Klonopin®, Gen-Xene®, Tranxene®, Diastat®, Dizac®, Valium®, Zarontin®, Peganone®, Felbatol®, Cerebyx®, Neurontin®, Mesantoin®, Mebaral®, Lamictal®, Celontin®, Paradione®, Milontin®, Dilantin®, Diphenylan Sodium®, Mysoline®, Gabitril®, Topamax®, Tridione®, Depacon®, Depakene®, Depakote®)

May lower the effect of the drug.



Steroids (Aristocort®, Kenacort®, Trilog®, AK-Pred®, Predalone TBA®, Predcor®, Deltasone®, Meticorten®, Orasone®, Medrol®, Decadron®, Hexadrol®, Maxidex®, Alphatrex®, Celestone®, Psorion®)

May lower the effect of the drug and herb.


Blood-thinning drugs/Anticoagulants (Coumadin®, Docoumarol®, Miradon®)

May lower the effect of the drug.


Digoxin ( Lanoxicaps®, Lanoxin®)

May cause a change in blood tests.


Estropipate(Ogen®, Ortho-Est®), Ethinyl estradiol (Estinyl®), Conjugated estrogens (Premarin®), Esterified estrogens (Estratab®, Menest®)

Nausea, bloating, polyps, dark patches on skin, high blood pressure, swelling, breast fullness, and migraine headaches.


Antidiabetic Medications/Blood Sugar Control Medications: Acetohexamide (Dymelor®), Chlorpropamide (Diabinese®), Glyburide (DiaBeta®, Micronase®), Metformin (Glucophage®), Tolazamide (Tolinase®), Tolbutamide (Orinase®). Insulin (Humalog®, Novolin®, Humulin®)

May lower blood sugar.Diabetics should avoid this herb.


Kava Kava

Anti-anxiety drugs and Sleeping Agents/ Benzodiazepines (Xanax®, Valium®, Ativan®, Halcion®, Klonopin®, Librium®, Serax®, Tranxene®).

Sedation, drowsiness, semi-comatose state, blackouts, and disorientation. Avoid activities requiring mental alertness. 1,3

Antipsychotic drugs/Tranquilizers (Thorazine®, Prolixin®, Compazine®, Phenergan®, Stelazine®, Mellaril®, Haldol®)

Sudden, intense movements of the neck and eyes.


Anti-Parkinson drugs (Eldepryl®, levodopa, Dopar®, Larodopa®, Sinemet®) and anti-nausea/anti-emetic drugs (Reglan®, Compazine®).

May lower the effect of the drug. May increase Parkinson’s symptoms.


Ma Huang

MAO Inhibitors (Nardil®, Parnate®, Marplan®)

Increased heart rate, increased blood pressure, irregular heart beat. Can be potentially fatal. 1

Nasal Decongestants (Sudafed®, Afrin®)

Increased heart rate, increased blood pressure, irregular heart beat. Can be potentially fatal. 2

Saw Palmetto


May lower the absorption of iron. Do not take both products at the same time. Take at least 1-2 hours apart. 5

St. John's Wort

Antidepressants or MAO Inhibitors (Celexa®, Paxil®, Prozac®, Zoloft®, Serzone®, Desyrel®, Elavil®, Pamelor®, Sinequan®, Nardil®, Parnate®, Marplan®, Analgesics (Ultram®)

Nausea, vomiting, headache, fatigue, confusion, nervousness, hyperactivity, anxiety, irritability. 1,2

Chemotherapeutic Agents (Etoposide, Paclitaxel, Vinblastine, Vincristine, etc.)

May decrease strength and effectiveness of the chemotherapy. 1,2

Immunosuppressant Drugs Cyclosporine (Neoral®, Gengraf®, Sandimmune®)

Lowers drug level. May cause

Rejection of organ transplant. 1,2

Digoxin (Lanoxin®, Lanoxicaps®)

Lowers drug level. May cause worsening of heart problems, i.e. congestive heart failure, irregular heart beat. 2

Birth Control Pills: Triphasil®, Ortho Novum®, and etc.

Lowers drug level. May decrease effectiveness (breakthrough bleeding, irregular menses). 1,2

HIV/AIDS Medications (Agenerase®, Norvir®, Crixivan®, Viracept®, Fortovase®, Invirase®)

Lowers drug level, and may cause resistance to other HIV/AIDS drugs.


Theophylline (TheoDur®, Slobid®)

Lowers drug levels; breathing difficulties, i.e. shortness of breath and wheezing. 1,2

Blood-thinning drugs/Anticoagulants: Warfarin (Coumadin®)

Change in blood clotting with increased risk of blood clots. 1,2

"Triptan" Migraine drugs (Imitrex®, Maxalt®, Zomig®, Amerge®)

Nausea, vomiting, headaches, fatigue, confusion, nervousness, hyperactivity, anxiety, irritability. 1,2

Valerian Alcohol

Drowsiness & impaired coordination when taken together. 5

Anti-anxiety drugs: Alprazolam (Xanax®).

May affect the nervous system; avoid operating heavy machinery. 5



1. The natural pharmacist herb-drug interactions for professionals. (2011). Retrieved from

2. Herbal medicine. (2006-2011). The Pharmacist's Letter. Retrieved from

3. FFacts and comparisons. (2006). The review of natural products-Monograph system. Retrieved from

4. Healthmall herbal remedies specific herb-drug interactions. (2011). Retrieved from

5. Barnes, J., Anderson, L., Phillipson, J. (2002). Herbal medicines: a guide for health-care professionals. 6th Ed. London: Pharmaceutical Press. 

Additional Information:

The following are some web sites to provide you with more information about herbal medicine and medicinal herbs.

American Botanical Council

American Dietetic Association

Healthworld Online's Herbal Medicine section

Herb Research Foundation

National Institute of Health Office of Dietary Supplements

Additional References:

Blumenthal, M. (1998). The complete German Commission E Monographs: Therapeutic guide to herbal medicines. Austin, Texas: American Botanical Council.

Fetrow, C., & Avila, R. (2000). The complete guide to herbal medicines. Springhouse, PA: Springhouse Corporation.

Foster, S., & Tyler, V. (1999). Tyler's honest herbal. A sensible guide to the use of herbs and related remedies (4th ed.). Binghamtom, NY: Haworth Herbal Press.

Hoffman, D. (1996). The complete illustrated holistic herbal: a safe and practical guide to making and using herbal remedies. Rockport, MA: Element Books./p>

Medline Plus. (2010). Herbal medicine. Retrieved from

Robbers, J., & Tyler, V. (1999). Tyler's™ herbs of choice: The therapeutic use of phytomedicinals. Binghamtom, NY: Haworth Herbal Press.

University of Maryland Medical Center. (2011). Herbal medicine. Retrieved from

Developed in 2002 by Jean Venn, Pharm D; Julie L. Smith, MS, RD, LD, CDE; Linda Pierce, PhD, RN at The University of Toledo for Caring~Web©.

Revised 2010, 2012

Last Updated: 6/27/22