Scientific Name: Rhamnus frangula
Other Names: Alder Buckthorn, Alder Dogwood, Arrow Wood, Black Dogwood, Dog Wood, European Buckthorn, Frangula Bark, Glossy Buckthorn

Who is this for?

Uses

Caution: Fresh Rhamnus frangula bark contains chemicals, including emodin, that cause severe vomiting. For use in medicine, the bark must be aged for at least one year.

More common in Europe than in North America, Rhamnus frangula is used as a laxative. It contains chemicals known as anthraquinones that stimulate intestinal movement and also attract more water to the intestines. Both actions promote the emptying of intestinal contents. Currently, however, other laxative products are more effective and less likely to cause side effects.

Fresh Rhamnus frangula bark should never be taken by mouth. Fresh bark or bark that has not been aged properly contains chemicals, including emodin, that can cause intense and extended vomiting. To be certain that potentially harmful chemicals have been removed, Rhamnus frangula bark must be air-dried for at least one year or aged under controlled heat in special facilities. Individuals should not try to collect and dry Rhamnus frangula on their own.

Rhamnus frangula works by irritating the lining of the gastrointestinal (GI) tract. For most individuals, GI irritation is minor. However, it can worsen inflammatory bowel conditions such as Crohn's disease and irritable bowel syndrome. In addition, Rhamnus frangula can complicate blocked bowels. Therefore individuals who have inflammatory bowel conditions or who have ever had bowel blockages should not use Rhamnus frangula.

Women who are pregnant or breastfeeding should avoid taking Rhamnus frangula because not enough is known about how it might affect developing babies and infants.

Rhamnus frangula should not be given to children under 12 years of age.

Precautions

No stimulant laxative, including Rhamnus frangula, should be used for longer than 7 days to 10 days. Chronic use of laxatives may lead to "lazy-bowel syndrome"--a dependence on laxatives to have any bowel movements as the muscles of the stomach and intestines gradually lose the ability to contract without being stimulated by the laxative.

Individuals who have unexplained abdominal or stomach pain may have conditions that could be worsened by Rhamnus frangula. Its use should be avoided by individuals with such pain.

Because Rhamnus frangula can decrease the water content of the body, individuals who use it should be sure to increase their intake of fluids while they are taking it or any other laxative.

What side effects should I watch for?

Major Side Effects

Rhamnus frangula's fresh bark or bark that has not been aged properly contains chemicals that cause severe vomiting.

If Rhamnus frangula is used in high doses or for extended periods, it can lead to reduced potassium levels in the body. Low potassium levels can result in muscle weakness and potentially dangerous changes in heart rhythm.

Occasionally, Rhamnus frangula has been associated with intense abdominal cramping.

Less Severe Side Effects

Taking Rhamnus frangula can darken the color of the stools and urine.

Regularly taking anthraquinone laxatives for many years may cause the inside of the intestines to darken from pink to brown in color. This condition, known as psuedomelanosis coli, is thought to result from discoloration by the pigments in the laxative products. Some researchers suggest that pseudomelanosis coli may lead to intestinal diseases, but no definite link has been established.

What interactions should I watch for?

Prescription Drugs

Because both corticosteroid drugs and Rhamnus frangula may promote the loss of potassium from the body, they should not be taken at the same time. Corticosteroids are used for a wide range of inflammatory conditions including arthritis, asthma, cancer, eye conditions, and skin infections. Commonly prescribed corticosteroids include:

• beclomethasone
• dexamethasone (Decadron)
• hydrocortisone
• methylprednisolone (Medrol)
• prednisolone
• prednisone
• triamcinolone

Diuretic drugs ("water pills"), such as furosemide and hydrochlorothiazide, can also reduce potassium levels in the body. If they are taken at the same time as Rhamnus frangula, potassium may become too low--possibly leading to muscle weakness and potentially dangerous changes in heart rhythm.

Rhamnus frangula can increase the risk of side effects such as dizziness, headache, heart rhythm changes, nausea, slow pulse, vision changes, and vomiting from the heart drug, digoxin. Rhamnus frangula should not be taken with digoxin.

Rhamnus frangula shortens the time that intestinal contents stay in the body. In theory, the effects of other drugs that are absorbed in the intestines may be reduced.

Non-prescription Drugs

Taking Rhamnus frangula at the same time as a commercial laxative may increase the laxative effects as well as the risk of potassium loss from the body. In general, it is not recommended to use both Rhamnus frangula and a laxative at the same time.

Herbal Products

Both Rhamnus frangula and extremely large amounts of true licorice (not licorice flavoring) can promote the loss of potassium from the body, potentially causing muscle weakness and changes in heart rhythm. The licorice ordinarily sold as candy in the United States does not contain true licorice. In any case, eating enough true licorice to present a problem is unlikely, if Rhamnus frangula is taken as directed.

Rhamnus frangula possibly could increase the laxative effects of other herbal laxatives including:

• Aloe
• Rhamnus cathartica
• Rhamnus purshiana
• Senna
• Yellow Dock

Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how Rhamnus frangula interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.

Should I take it?

Commonly known as alder buckthorn or glossy alder, Rhamnus frangula grows as a small tree throughout Britain, much of Europe and the U.S. Although it is called dog wood in many parts of the world, Rhamnus frangula is not the same as the flowering dogwood trees common in the American Midwest. Unlike related trees, it does not have thorns. Its shiny leaves, water tolerance, and fast growth make it popular for fence rows in damp areas of Britain. Rhamnus frangula bears small greenish flowers in the spring and dark red, purple, or black berries in the fall. It was much valued by 19th century weavers because its unripe berries produce a greenish dye; its ripe berries a blue-gray color; and its leaves and twigs a bright yellow, which turns black if iron is added.

During the summer, bark is collected from Rhamnus frangula branches that have been cut for use in making charcoal. The bark must be dried and aged for at least one year (if dried naturally) or processed under specific conditions (if cured in a commercial facility). Improperly cured or fresh bark contains chemicals, including emodin, that cause severe vomiting.

Dosage and Administration

Caution: Fresh Rhamnus frangula should never be taken orally because it contains emodin and other chemicals that cause severe vomiting. Individuals who decide to use Rhamnus frangula are advised to use a commercial product rather than collecting it from trees.

Rhamnus frangula is available as capsules, liquid extracts, or tablets that all have been made from the tree bark after it has been aged, dried, and powdered. Commercial preparations of Rhamnus frangula usually are standardized according to their content of an anthraquinone known as glucofrangulin A. Standardization by the manufacturer should assure the same amount of active ingredient in every batch of the commercial preparation. Although dosing recommendations for Rhamnus frangula are not consistent, the European agency responsible for herbal medicines sets the maximum amount of glucofrangulin A at 30 mg per day.

In some countries, Rhamnus frangula may be purchased in bulk as bark chunks or powder. Rhamnus frangula tea is made by soaking 2000 mg (2 grams) of dried, aged bark in about 5 ounces of boiling water for 5 minutes to 10 minutes, straining out the solid particles, and drinking the liquid. Because Rhamnus frangula has a strongly bitter taste, the tea is often sweetened or flavored to make it taste better. Common recommendations for the use of Rhamnus frangula bark powder range from 500 mg to 2,500 mg (0.5 gram to 2.5 grams) of the aged, powdered bark per day. Because it may take up to 8 hours to work, Rhamnus frangula is often taken at bedtime. Individuals who decide to use it, should follow exactly the recommendations on the package of the product that is purchased.

Only the smallest amount of Rhamnus frangula that produces a stool should be taken. Rhamnus frangula should be used only long enough to correct constipation--no longer than 7 days to 10 days because prolonged use has been associated with the loss of potassium from the body. Potassium levels that are too low can cause muscle weakness and heart rhythm changes. If diarrhea occurs, its use should be stopped.

Summary

Aged bark of Rhamnus frangula is used as a laxative.

Risks

Due to its irritating effect on the gastrointestinal (GI) tract, Rhamnus frangula should not be used by individuals with inflammatory bowel diseases. Children under the age of 12 and women who are pregnant or breast feeding should also avoid its use, as should those who have or have had intestinal blockages. Abdominal or stomach pain that does not have obvious sources may be an indication of a condition that using Rhamnus frangula could worsen. No laxative should be used if such pain is present. Rhamnus frangula should not be used for longer than 10 days at a time.

Side Effects

Fresh Rhamnus frangula bark may cause intense vomiting. Side effects associated with dried Rhamnus frangula include stomach cramps and discolored stools or urine.

Interactions

If Rhamnus frangula is taken at the same time as corticosteroids, water pills, or large amounts of licorice; potassium levels in the body may get too low. If it is taken at the same time as digoxin, Rhamnus frangula could increase the risk of digoxin's side effects. Rhamnus frangula can increase the laxative effects and the risk of low potassium levels if it is taken with laxative medications or herbals.

Last Revised April 17, 2008

References

Anon. Rhamnus frangula. Weed Ecology Lab. Purdue University. No Date Given. Available at: http://btny.agriculture.purdue.edu/buckthorn/page4.asp Accessed March 31, 2003.

Dharmananda S. Safety issues affecting herbs: how long can stimulant laxatives be used? The Institute for Traditional Medicine. March 2002. Available at: http://www.itmonline.org/arts/laxatives.htm. Accessed May 23, 2007.

European Medicines Agency. Committee for Herbal Medicinal Products. Evaluation of medicines for human use. Community herbal monograph on frangula bark (frangulae cortex). March 9, 2006.Available at: http://www.emea.europa.eu/pdfs/human/hmpc/7630706en.pdf. Accessed May 24, 2007.

European Scientific Cooperative on Phytotherapy. Frangulae cortex, frangula bark. Monographs on the Medicinal Uses of Plant Drugs. Exeter, UK: University of Exeter, Centre for Contemporary Health Studies, 1997.

Grieve M. Buckthorn (Alder). In: A Modern Herbal. New York: Dover Publishers, 1971. Available at: http://www.botanical.com/botanical/mgmh/mgmh.html Posted 1995. Accessed March 28, 2003.

Kupchan SM, Karim A. Tumor inhibitors. 114. Aloe emodin: antileukemic principle isolated from Rhamnus frangula L. Lloydia. 1976;39(4):223-224.

Jellin JM, Gregory P, Batz F, Hitchens K, et al, eds. Pharmacist's Letter/Prescriber's Letter. Natural Medicines Comprehensive Database, 3rd Edition. Stockton CA: Therapeutic Research Facility, 2000.

Manojlovic NT, Solujic S, Sukdolak S, Milosev M. Antifungal activity of Rubia tinctorum, Rhamnus frangula and Caloplaca cerina. Fitoterapia. 2005;76(2):244-246.

National Institutes of Health. National Toxicology Program. NTP toxicology and carcinogenesis studies of emodin (CAS no. 518-82-1) feed studies in F344/n rats and B6C3F1 mice. National Toxicology Program Technical Report Service. 2001;493:1-278.

Natural Medicines Comprehensive Database, Online Edition. Pharmacist's Letter/Prescriber's Letter. Stockton CA: Therapeutic Research Facility, 2006. Available at: http://www.pharmacistsletter.com/(S(ulqz3s45omt3ag55um4kj345))/home.aspx?li=1&st=1&cs=&s=ND.

Rychener M, Steiger W. Purification, glucose-6-phosphate dehydrogenase inhibition, and HPLC analysis of four 1,8-dihydroxyanthrones [article in German] Pharm Acta Helvetica. 1989;64(1):8-15.

Siegers CP, von Hertzberg-Lottin E, Otte M, Schneider B. Anthranoid laxative abuse--a risk for colorectal cancer? Gut. 1993;34(8):1099-1101.

Sydiskis RJ, Owen DG, Lohr JL, Rosler KH, Blomster RN. Inactivation of enveloped viruses by anthraquinones extracted from plants. Antimicrobial Agents in Chemotherapy. 1991;35(12):2463-2466.

van den Berg AJ, Labadie RP. Anthraquinones, anthrones and dianthrones in callus cultures of Rhamnus frangula and Rhamnus purshiana. Planta Medica. 1984;50(5):449-451.

van den Dikkenberg MI, Holtkamp BM. Alder buckthorn poisoning in horses. [Article in Dutch] Tijdschr Diergeneeskd. 1987;112(6):340-341.

Willems M, van Buuren HR, de Krijger R. Anthranoid self-medication causing rapid development of melanosis coli. Netherlands Journal of Medicine. 2003;61(1):22-24.

Last Revised Aprill 17, 2008

Note: The above information is not intended to replace the advice of your physician, pharmacist, or other healthcare professional. It is not meant to indicate that the use of the product is safe, appropriate, or effective for you.

In general, herbal products are not subject to review or approval by the U.S. Food and Drug Administration (FDA). They are not required to be standardized, meaning that the amounts of active ingredients or contaminants they contain may vary between brands or between different batches of the same brand. Not all of the risks, side effects, or interactions associated with the use of herbal products are known because few reliable studies of their use in humans have been done.

This information is provided for your education only. Please share this information with your healthcare provider and be sure that you talk to your doctor and pharmacist about all the prescription and non-prescription medicines you take before you begin to use any herbal product.

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