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Quercetin is a flavonoid—a substance found in fruits, flowers, and vegetables—that, among other functions, gives them their color. Flavonoids have antioxidant properties, which help protect against disease, as well as anti-inflammatory and antihistamine effects.
Quercetin offers a variety of potential therapeutic uses, primarily in the prevention and treatment of the following conditions.
Quercetin may also be beneficial in the treatment of dysentery (an intestinal infection causing severe diarrhea), gout (a disease where crystals of uric acid, a component of urine, are deposited in the joints and cause swelling), and psoriasis (a chronic skin disease).
Fruits and vegetables—particularly citrus fruits, apples, onions, parsley, tea, and red wine—are the primary dietary sources of quercetin.
Quercetin is available as a supplement in several strengths in powder or capsule form. It is often packaged with bromelain as an anti-inflammatory agent. Flavonoid-rich extracts include those from grape seed, bilberry, Ginkgo biloba, and green tea.
How to Take It
Recommended dosages of quercetin vary depending on the health condition being treated. The following are guidelines for some of its common uses.
There are no known reported problems with the use of quercetin.
No harmful drug interactions have been reported.
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