By Elizabeth Lipski, PhD, CCN

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Quercetin is best known for its effectiveness in asthma, allergy, and as an anti-viral agent. It inhibits the release of mast cell histamine from IgE mediated allergy. Histamines cause our nose to run, eyes to tear, and our skin to itch. Quercetin also inhibits IgG histamine release, in a way similar to the prescription drug Cromolyn sodium. In asthma, quercetin blocks the production of cyclo-oxygenase and leukotrienes which trigger inflammation and swelling of airways which makes it so difficult for us to breathe. Quercetin has healing properties which NSAID medications and anti-histamines lack. Quercetin stimulates structural and cellular repair of collagen, elastin, and basement membranes, which are needed to anchor and orient all the cells in your body. This helps the lungs, sinuses, and entire respiratory system get stronger over time. In addition to providing symptomatic relief, quercetin triggers true regeneration of tissues so that over time your allergies and respiratory symptoms bother you less and less.

In contrast, anti-histamines work by blocking the body’s production of histamines so we temporarily feel better. But anti-histamines don’t deal with the underlying cause of your allergies. Non-steroidal anti-inflammatory drugs (NSAIDS) like aspirin, Motrin, Celebra and Tylenol stop pain by blocking ecoisanoid synthesis. They block both the prostaglandins that cause pain and those that promote healing. When we use these pain medications, we block our body’s ability to heal. Their use will never help you ultimately regain your health.

Chronic inflammation and allergies is our body’s way of telling us to pay attention—to slow down and help the body heal by eating healthful foods, taking the appropriate nutritional and herbal supplements, nurturing ourselves more, and taking the time to heal. When we are healthy, our body has the capacity to easily repair itself and we never even know of the trauma. When our body fails to easily heal, it tells us that we are deficit spending and that it is time to pay attention and take action. And sometimes that action is “rest!”

Quercetin is the most potent of the bioflavinoids and has more far-reaching abilities than other bioflavinoids such as rutin, hesperidin, and rose hips. These compounds were first discovered in the 1930’s by Albert Szent-Gyorgy, winner of the Nobel prize for his work on vitamin C. Historically quercetin was called "vitamin P", along with another bioflavinoid, rutin. These flavinoid complexes are naturally found in our foods, primarily in fruits and vegetables. Our average daily intake of quercetin is about 25 mg. Foods with the highest levels include: onions, apples, tea, and to a lesser extent green leafy vegetables and beans. Bioflavinoids as a group help us keep our blood vessels strong and help with repair of cartilage, tendons, and ligaments.

Active flavinoid/flavinol combinations (like quercetin dihydrate and grape seed OPC, stimulate repair of inflamed, swollen and often painful tissues throughout the body. In contrast NSAIDS suppress repair of inflamed tissues by blocking prostaglandin formation. Both give relief. One solves the problem, the other increases our repair deficit.


Healthy people can take 1-2 tablets daily.
For chronic allergy, pain, inflammation, asthma, or sinusitis take 2-16 tablets daily.

For a very acute problem the body has a high demand for these substances. Dosage can be 2 tablets every two hours. There has been no evidence of adverse affects at the highest dosage levels with these specific compounds. (Use of less active quercetin or bioflavinoids can trigger an allergic or inflammatory response.)

The Many Faces of Quercetin

One of the beauties of nutrient therapy is that each nutrient has so many positive effects on the body. Quercetin displays this quite elegantly. Although our focus in this newsletter is quercetin’s ability to affect allergies, sinusitis, and bronchitis, it has other amazing properties.

Antioxidant Effect Highest of any flavinoid

Free radical scavenger especially of superoxide radicals and lipid peroxy radicals.


High quercetin dietary intake has been shown to lower the incidence of strokes and cardiovascular disease and to prevent the oxidization of LDL cholesterol.


Recent studies have shown quercetin to have bone-building effects.


Quercetin lessens the pain and inflammation of acute pancreatitis infection.

Neurological problems of Diabetes

Quercetin blocks the accumulation of sorbitol in eyes, nerves and kidneys so is useful for the prevention of neurological problems of diabetes.

Anti-Cancer Properties

Quercetin has also been shown to have anti-cancer properties in squamous cell cancers and leukemia. It is also being used in with cisplatin, a common chemotherapy drug, for women with ovarian cancer. Quercetin lessens the toxic effect of the cisplatin while enhancing its anti-cancer effects.GoutQuercetin inhibits uric acid production which is useful for people with gout.


Quercetin inhibitis the growth of Helicobacter pylori, the bacteria responsible for most stomach and duodenal ulcers.

HIV Virus

Quercetin is also a potent reverse transcriptase inhibitor, so is useful in treating the HIV virus.


Men taking 500 mg quercetin BID or TID had reduction in inflammation and irritation. There was no change in urinary frequency.

© Elizabeth Lipski, PhD, CCN


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