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As little as 200 mg of quercetin per day competes with steroid-type anti-allergic drugs


If you’re among the millions of people with allergic rhinitis, also called as allergies, despite the nice weather, spring and summer can be miserable. Grasses, weeds and pollen from trees as well as dust and dander can trigger itchy eyes, nasal congestion, sleep disorder and other discomforts, which are symptoms of allergic reactions.

The use of anticholinergic, antihistamine drugs or steroids are effective, but they’re not without adverse effects. Fortunately, drugs are not the only option. Supporting your immune system and relieving allergy symptoms can be achieved drug-free, by nutrition. One especially useful nutrient to consider is a natural antihistamine, quercetin.

Table of Contents

Allergy and the rise in allergic diseases


Allergies occur when your body reacts to something that’s normally harmless like pollen, dust, bee venom, pet dander or a food. Your immune system produces substances known as antibodies that identify a particular allergen as harmful, even though it isn’t.

Studies have suggested that the increase in the prevalence of allergic disorders that has occurred over the past few decades is attributable to several factors:

Quercetin and its role in the treatment of allergic symptoms


Quercetin is a naturally occurring, antioxidant-rich polyphenol flavonoid that has been reported to have immunomodulating and anti-inflammatory actions. It has anti-allergic functions such as the inhibition of histamine production and pro-inflammatory mediators, the regulation of Th1/Th2 stability, and the ability to decrease the antigen-specific IgE antibody released by B cells. Quercetin has a main role in anti-inflammatory and immunomodulatory functions.

An in vitro study demonstrated the effect of quercetin in modulating the immune function by inhibiting mast cell activity and histamine release, suppressing eosinophilic inflammation.

An up-to-date research conducted on humans with allergic symptoms

Recently, a randomized, placebo-controlled, double-blind parallel-group study was conducted on 66 allergic patients aged 22 to 78 years, involving both men and women. Patients were given a test product containing 200 mg quercetin or the control product, placebo, without the active ingredient, daily for 4 weeks. Everything else was held the same between the two groups, thus the outcome could be attributed to the active treatment.

The Japanese Rhino-conjunctivitis Quality of Life Questionnaire (JRQLQ) scores and physical examinations, blood tests, urinalysis, and allergic rhinitis-related tests were conducted at baseline, 2 and 4 weeks after test product or placebo ingestion.

After evaluation of the test results, the outcome showed significant differences between the 2 groups ingesting 200 mg of quercetin or the placebo, daily. Those who took 200 mg of quercetin showed significant improvement in subjective evaluation, primarily in the influence on sleep; and objective evaluation, such as severity of allergic rhinitis and nasal discharge eosinophil count, thus alleviating the effect of allergic rhinitis.

Read the full research: Effects of repeated oral intake of a quercetin-containing supplement on allergic reaction: a randomized, placebo-controlled, double-blind parallel-group study

Another source of allergy relief: Vitamin C

vitamin C

Besides boosting the immune system with its antioxidant and anti-inflammatory properties, Vitamin C also acts as a natural antihistamine. Since allergies are an immune-system response, an adequate vitamin C level is important.

The combination of quercetin and vitamin C might offer a promising remedy for allergies. Individually, they both address histamine levels in the body. However, when combined, the two antioxidants show synergic effects to reduce the amount of histamine produced by the immune system and cut down on allergy symptoms.


Allergic disorders have been rapidly increasing worldwide. There is a growing demand for new sources of anti-allergic bioactive compounds, especially for natural compounds without adverse side-effects. Recently, scientific attention has turned towards flavonoids, mostly quercetin. Quercetin shows high antioxidant, anti-inflammatory and anti-allergic properties that have been proven by many in vivo and in vitro studies. The results of these prove the unique position of quercetin in the treatment of allergic disorders. To further increase its positive effects, taking quercetin together with vitamin C is a great choice.