Goldenseal (Hydrastis canadensis) was originally introduced to early American settlers by Native American tribes, who used it primarily for skin problems, digestive disorders, and as a wash for sore eyes. It is now one of the most popular herbs in the United States, although there is little scientific evidence for its effects.

Part of goldenseal's popularity is likely due to the rumor that taking the herb can help mask a positive test for illegal drugs. There's no real evidence that it works, and several studies have reported that taking goldenseal does not alter the results of a drug test.

Goldenseal is often combined with echinacea in cold remedies, but there is no evidence that it works. However, as goldenseal has soared in popularity, it has become overharvested. In 1997, the Convention on International Trade in Endangered Species of Wild Fauna and Flora reported that goldenseal is at risk of becoming an endangered species. As a result, the international trade of goldenseal continues to be closely controlled and monitored.

Goldenseal is a small plant with a single hairy stem. It has two five-lobed, jagged leaves, small flowers, and raspberry-like fruit. The bitter-tasting rhizome, or root, is a bright yellow-brown in color, twisted, and wrinkled. Goldenseal can be found growing wild in rich, shady soil in the northern United States, but is now grown mostly on farms.

Goldenseal contains a compound called berberine that kills many types of bacteria in test tubes, including the ones that cause diarrhea. Berberine has also been shown to kill a wide range of other types of germs in test tubes, such as those that cause candida (yeast) infections and various parasites such as tapeworms and Giardia. Berberine may also activate white blood cells, making them more effective at fighting infection and strengthening the immune system. Berberine is sometimes used as an antibiotic and disinfectant, both externally and internally. Berberine may also be useful in heart failure. However, it's traditionally thought that the berberine in goldenseal isn't absorbed well in the intestinal tract.

Antibiotic or Immune Booster

Today, goldenseal is marketed as a tonic to aid digestion, sooth upset stomach, and as an antibacterial agent. It is considered a natural antibiotic and is most often combined with echinacea in preparations designed to strengthen the immune system. However, only one study found that goldenseal might help boost white blood cells (a measure of the infection-fighting ability of the immune system), and it wasn't well designed.

Upper respiratory problems

Goldenseal is often found in herbal remedies for hay fever (also called allergic rhinitis), colds, and the flu. There's no real evidence that it works in humans to treat upper respiratory infections or allergies, however. It may help ease a sore throat, which often accompanies cold or flu.

Minor wounds

Because goldenseal appears to have antiseptic properties in test tubes, it's sometimes used to disinfect cuts and scrapes.

Other

It is commonly used to treat several skin, eye, and mucous membrane inflammatory and infectious conditions (such as sinusitis, conjunctivitis, and urinary tract infections). It is also available in mouthwashes for sore throats and canker sores.

Goldenseal has not been investigated in many scientific studies. Some trials have looked at berberine, one of the active compounds in goldenseal. Berberine is widely used in Traditional Chinese Medicine to treat dysentery and infectious diarrhea. Berberine may be effective in humans for malaria, heart failure, and various types of infections, including upper respiratory problems. It may also dilate blood vessels and help in treating heart failure. However, oral goldenseal contains only trace amounts of berberine, so it's impossible to say whether the herb would be effective or not.

Goldenseal supplements are available as tablets and capsules (containing the powdered root), liquid extracts, and glycerites (low-alcohol extracts). Goldenseal is commonly found in combination with the herb echinacea.

Pediatric

Goldenseal is not recommended for children unless under a doctor's supervision.

Adult

• Capsules or tablets: 500 - 1,000 mg, up to 3 times daily
• Standardized extract: 30 - 120 mg, up to 3 times daily
• Tinctures (1:5): 2 - 3 mL, three times daily
• For disinfecting cuts, scrapes, boils, and acne: Place goldenseal liquid extract on a clean cloth, and press the cloth gently on the affected area.
• For sore throat, gums, or mouth, make a mouthwash as follows: In one cup of warm water, mix 1/4 tsp salt and 1/2 tsp (or the contents of one capsule) of goldenseal powder. (It will not dissolve completely.) Rinse and spit out.
• For vaginal irritation, make a goldenseal douche as follows: Mix 1/4 tsp salt and 1/2 tsp (or the contents of one capsule) of goldenseal powder in 1 cup of warm water. Let the mixture settle, and strain out any suspended particles before using it. (Keep the mixture as clean as you can.) Douching can make you more susceptible to certain kinds of vaginal infections. See your health care provider if your symptoms do not improve after a few days.
• For eye infections and irritations, make an eyewash as follows: Use one cup of sterile water with 1/4 tsp salt and 1/2 tsp goldenseal and strain out all particles. Discard if the solution becomes cloudy, which indicates bacterial growth or spoilage.

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain components that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider qualified in the field of botanical medicine.

Pregnant or breastfeeding women should not use goldenseal.

People with high blood pressure, liver disease, or heart disease should ask their doctor before taking goldenseal.

Goldenseal can irritate the skin, mouth, throat, and vagina. It may also cause an increased sensitivity to sunlight.

Goldenseal may interfere with the metabolism and effectiveness of certain medications. If you are taking prescription or non-prescription medications, ask your doctor before taking goldenseal.

A few studies report interactions between berberine (a major component of goldenseal) and prescription or non-prescription medicines.

Tetracycline -- One study reported that berberine may decrease the effectiveness of tetracycline antibiotics.

Anticoagulants (blood thinners) -- Theoretically, goldenseal and berberine could increase the risk of bleeding, especially if you take blood thinners. These medications include:

• Warfarin (Coumadin)
• Aspirin

Other laboratory studies report that berberine may change liver metabolism, possibly affecting the levels of medications processed in the liver. Several studies suggest that goldenseal itself does not interact with medicines metabolized by the liver (including an antiviral drug used in HIV infection and digoxin). However, if you are taking prescription or non-prescription medications, ask your doctor before taking goldenseal.

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