Native to temperate regions located in Asia, Europe, and the Northeastern United States, this deciduous shrub has been used for centuries as an effective nutritional supplement. Barberry is thought to have been used in ancient Egyptian and Asian civilizations. Even more recently, English colonists and Native Americans used the acidic fruit of the barberry plant (Fructis Berberidis) for both a food and medicinal tool. In traditional folk medicine, barberry has also been used in ailments ranging from a simple fever, to even more serious diseases like malaria. [1, 2]
Barberry’s medicinal properties are the result of its chemical constituents berberine, columbamine, and oxyacanthine. Of these compounds, the berberine alkaloid has received the most research. It has been used in various clinical applications for the treatment of many different conditions. Berberine alkaloids are also found in another popular herbal supplement, goldenseal (Hydrastis canadensis), and is thought to be the main medicinal compound in this herb as well. Today, there are many diverse conditions treated with barberry. Its most popular use, however, continues to be within the arenas of specific biliary disorders, or conditions relating to the bile ducts or gallbladder. 
Barberry is available in various supplemental forms. Capsules, fluid extracts, ointments, and tinctures represent the most popular and effective delivery methods. The most potent barberry supplements contain a 8-12 % standardized extract of isoquinoline alkaloids. This chemical compound is extracted from the root bark, stem, and fruit of the shrub. The isoquinoline alkaloids are often combined with other bitter herbs to form more effective and potent synergistic combinations.
Barberries may also be harvested directly from the plant for consumption. In the past, these fruits were used to make various jams, preserves, syrups, teas, and were even candied. The dietary consumption of ripe barberry fruits has, however, proven to be hazardous. The USDA has banned barberry cultivation, due to the likelihood of “rust” developing on the barberry shrub. The aforementioned “rust” describes a particular form of toxic fungus, potentially fatal in humans.
Oxyacanthine, a primary constituent of barberry, may be effective at eradicated harmful microbes.  Recent study suggests that this compound may be responsible for barberry’s reputed fungicidal, anti-inflammatory, as possible astringent properties. Duke University’s Handbook of Medicinal Herbs has reported indications of barberry being stronger than certain prescribed medications in the treatment against staphylococcus, streptococcus, and candida (yeast).  Medical literature also suggests that the chemical constituents of barberry may possess certain antihelicobacter and anti-parasitic properties.
Diarrhea and GI distress
Berberine may be an effective treatment of food poisoning and traveler’s related diarrhea.  Although the mechanism of this action is not completely understood, it is theorized that barberry’s constituents inhibit certain bacteria from attaching to vulnerable cellular membranes. Native Americans and early European settlers used barberry as a treatment for not only diarrhea, but also common indigestion, liver dysfunction, and urinary tract infections. [1, 3, 7] Barberry may be equally effective against both heartburn, and complications resulting from ulcers.
Monographs by Germany’s Commission E have indicated that barberry possesses certain stimulatory activities; primarily in the circulatory, digestive, and respiratory systems.  Barberry may also hold certain antioxidant properties, while being equally effective as an anti-inflammatory agent.  Barberry tonics may also assist in the amelioration of gallstones and jaundice, while regulating bile production and flow. Research continues to discover additional advantageous properties of the unique alkaloids found within the barberry plant.
There have been no established dosages for any barberry-containing supplements. Dosages are often dependant upon two specific factors; 1 - the form of the supplement being used, and 2 - the condition being treated. The graph below depicts a mixture of uses and intake examples for different supplemental forms of barberry. These dosages are approximate and are not intended to replace the dosage instructions given by the individual supplement manufacturer.
|Supplemental Form||Condition||Common Dosage|
|Tincture||Digestive||2-5 milliliters, 15-20 minutes prior to meal|
|Standardized Extracts (8-12%)||Infection||250-500 milligrams, 3 x per day|
|Ointment||Skin Disorders||10% extract, applied 3 x per day|
|Teas||Misc.||2-4 grams (1-2Tbsp.) dried root in 2/3 cup water, 3 x per day|
Barberry does contain some active substances, which may cause barberry sensitive persons to develop gastrointestinal discomfort. Prolonged and excessive dosages of barberry supplements may result in symptoms of lethargy, skin, eye, and nose irritation, and possibly, kidney irritation. 
Pregnant women are advised not to take any barberry containing supplements, as the berberine alkaloids may increase the risk of jaundice in infants by interfering with their normal liver functioning.  More research is necessary to further establish berberine’s effect on pregnant women and infants. Nevertheless, both pregnant and breast-feeding mothers should by extremely cautious when taking any nutritional supplement.
As barberry is an external food source, there are no nutritional deficiencies concerning the chemical constituents of this plant.
1. Jellin JM, Batz F, Hitchens K. Natural Medicines Comprehensive Database. Third Edition. Stockton, California: Therapeutic Research Faculty, 2000.
2. Hostettmann, K, Marston A, Maillard M, Hamburger M. ed. Phytochemistry of Plants Used in Traditional Medicine. Oxford: Clarendon Press, 1995.
3. Gruenwald J, et.al. PDR for Herbal Medicines. First Edition. Montvale, NJ: Medical Economics Company, Inc., 1998.
4. Amin AH, Subbaiah TV, Amin AH. Berberine Sulfate: Antimicrobial activity, bioassay and mode of action. Can J Microbiol 1969; 15:1067-76.
5. Duke JA, et. al. Handbook of Medicinal Herbs. Second Edition. Boca Raton, FL: CRC Press. 2002.]
6. Rabbani GH, Butler T, Knight J, et al. Randomized controlled trial of berberine sulfate therapy for diarrhea due to enterotoxigenic Escherichia coli and Vibrio cholerae. J Infect Dis 1987; 155:979-84.
7. Foster S, Tyler VE. Tyler’s Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. Fourth Edition. New York: The Haworth Herbal Press, 1999.
8. Blumenthal M, et. al. ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Austin: American Botanical Council, 1998.
9. Ju HS, Li XJ, Zhao BL, et al. Scavenging effect of berbamine on active oxygen radicals in phorbol ester-stimulated human polymorphonuclear leukocytes. Biochem Pharmacol 1990; 39:1673-8.
10. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete Commission E Monographs; Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative Medicine Communications, 1998, 309-10.
11. Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate, 1993; 63:2-1-8.