This species is native to Europe and was brought to North America by early settlers. It is now grown thoroughout North America and is closely related to the species, Oregon grape (berberis aquifolium), which is native to North America.
Traditionally barberry was used in Europe and America for treating a large number of conditions. The the most notable is infections and stomach problems. It has also been used internally to treat skin conditions.
There are a couple active constituents of barberry. The alkaloid, berberine, receives the most research and widest acclaim as the active component out of all the active constituents of barberry.
Berberine is antibacterial and has been shown to kill amoebae in a test tube study. It inhibits bacteria from attaching to human cells, which helps prevent infection. It has been used to treat diarrhea caused by bacteria, such as E. coli. Berberine can also stimulate some of the immune system cells to function better.
Berbamine is another alkaloid that is found in barberry. It can be used to help reduce inflammation and is also used as an antioxidant. The bitter compounds in barberry, including the alkaloids mentioned above, can stimulate digestive functions if taken following meals.
It is recommended to take 1-2 grams of barberry three times daily if it is dried bark in a pill form with a full glass of water. 2-3ml three times daily should be taken if it is a liquid extract. If it is in tincture form, take 2-4ml three times daily.
The effects of barberry on pregnant or nursing women have not been reported. It is not known whether or not it can hurt the unborn or nursing baby. There is also no information available regarding the use of barberry by children.
You should talk to your doctor, pharmacist, or health care professional before taking barberry if you are pregnant or nursing, have a medical condition, are taking other medicines or herbal/health supplements, or have allergies (especially to plants).