Herbal Medicines: Consult with Your Doctor Before Use


One in three Americans has taken herbal medicines in the past year to improve health. Annual purchases soar each year costing $5 billion in sales.1

Herbals that have been proven safe and effective deserve to be considered valid options for improving health. However, the effectiveness of many herbs is still not proven, and it's often difficult to tell fact from fiction in books and computer resources about herbs.2 Many are either for or against herbal medicines, making it difficult to get a true picture of the benefits and risks of using these products.

One important factor to keep in mind is that herbs act like medicines in the body and can cause strong unwanted effects. The table below lists the 10 most common herbs used in the US, possible uses, side effects, and warnings or interactions with other medicines. As with prescription and over-the-counter medicines, dangerous side effects can occur when taking herbs, particularly if too much of the product is used. To cite one example, chamomile should not be taken if you have a history of asthma or allergic dermatitis, or if you take warfarin (Coumadin) or other blood thinners.

The herb should also be avoided if you are pregnant or breastfeeding, because it may trigger a miscarriage.2 Yet, most people would not think to look into the safety of drinking a cup of chamomile tea each night to help with sleep.

If you use herbal medicines, consult with your doctor before you start taking the herb, or let your physician and pharmacist know if you are already taking these products. Unfortunately, some studies have found that most patients don't tell their doctors they are taking herbal medicines.2 In some cases, patients don't consider herbs to be medicine; in other cases, they believe their doctors will criticize them for using the herbs. However, doctors need to know if you are taking these products so that they can accurately judge whether particular symptoms are related to a medical illness or a side effect from an herbal medicine. Those who take herbal products should also keep a reliable, unbiased reference on hand. The National Library of Medicine and National Institutes of Health offer a comprehensive, free Internet resource that can be accessed at: www.nlm.nih.gov/medlineplus/herbalmedicine.html.

HerbWhy People May Use This HerbExamples of Side EffectsExamples of Warnings/Interactions
Echinacea Treatment or prevention of colds, urinary bladder infections, burns Rash, dizziness, itching Immune system can be overstimulated and then depressed with long-term use Immune system can be overstimulated and then depressed with long-term use
St. John's wort Internal use: depression, anxiety; Topical use: burns, skin lesions Sun sensitivity, upset stomach, dry mouth, restlessness, trouble sleeping, constipation May interact with birth control medicines, immunosuppressants, cancer medicines, and other medicines for depression
Gingko biloba Poor memory, poor leg circulation, dizziness, ringing in the ears Upset stomach, headache, seizures, unusual bleeding or bruising. May interact with blood thinners like warfarin
Garlic High blood pressure, high cholesterol, fatty deposits in arteries Upset stomach, indigestion, nausea, allergic reactions, dizziness, sweating, underactive thyroid, stimulation of the uterus May interact with blood thinners like warfarin
Saw palmetto Benign prostate enlargement Abdominal or back pain, diarrhea, nausea, painful urination, trouble emptying bladder Use only if diagnosed with benign prostate enlargement and approved by your doctor
Ginseng General health promotion and to increase energy levels, sexual function, athletic ability, fertility Diarrhea, high blood pressure, insomnia, nervousness, chest pain, breast pain, rapid pulse, vaginal bleeding May interact with drugs used to treat diabetes, blood thinners, depression medicines
Goldenseal Internal use: upper respiratory infections; Topical use: inflammation, antiseptic to clean wounds, skin infections Diarrhea, high blood pressure, mouth sores, nausea, numbness or tingling in arms or legs, seizures, dangerous heart rhythms Taking large doses can cause death; may interact with heart and blood pressure medicines and blood thinners
Aloe Topical use: wound healing, itching, burns; Internal use not recommended although oral capsules/extracts are available Delayed wound healing, diarrhea, reddish urine, dehydration Avoid taking aloe capsules if you have kidney or heart disease; may interact with digoxin, steroids, water pills
Siberian ginseng General health promotion and to increase energy levels, sexual function, athletic ability, fertility Diarrhea, high blood pressure, insomnia, nervousness, blurred vision, pimples, vaginal bleeding, low blood sugar in diabetic patients Don't use when taking vitamins B1, B2, and C; don't use for more than 3 weeks; may interact with digoxin
Valerian Insomnia, anxiety, muscle spasms Fatigue, headaches, irregular heartbeats, excitability, nausea May interact with sedatives; don't use if you have liver disease


1) Garg V, Hershey C. The top 10 herbal therapies. Postgraduate Medicine online 2003;8. Retrieved May 12, 2008, at:www.postgradmed.com/issues/2003/08_03/garg.shtml.

2) Fetrow CW, Avila JR. The complete guide to herbal medicines. 2000; Springhouse, PA:
Springhouse Corporation.

Created on May 1, 2008

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