Allergies Home > Quercetin Side Effects

Headaches and tingling of the hands or feet are some of the possible bothersome side effects that have been reported with oral use of quercetin. With the IV form of the supplement, side effects include sweating, flushing, and shortness of breath. While most side effects of quercetin are mild, some are potentially serious and require immediate medical attention, including kidney damage and allergic reactions.

Does Quercetin Cause Side Effects?

Even though it is a natural product, quercetin may cause side effects, although short-term use of the supplement appears to be unlikely to cause serious side effects in most healthy adults. At this time, the side effects of long-term use (or high doses of the supplement) are currently unknown.
People often assume that natural products are always safe and free of side effects. However, this is simply not the case. It is reasonable to assume that any natural product with the capability to have medicinal properties may also have side effects.
(This article covers many, but not all, of the possible side effects with quercetin. Your healthcare provider can discuss a more complete list of side effects with you.)

Possible Side Effects of Quercetin

Possible bothersome side effects that have been reported with oral use of quercetin include:
  • Headaches
  • Tingling of the hands or feet.
Possible side effects of quercetin given by IV include:
  • Flushing
  • Sweating
  • Shortness of breath
  • Nausea and vomiting.

Serious Side Effects

Possible serious quercetin side effects (which should be reported to your healthcare provider immediately) include:
  • Kidney damage (which has been seen with high doses given by IV)
  • Symptoms of an allergic reaction, such as:


    • A rash
    • Hives
    • Itching
    • Swelling of the mouth, lips, tongue, or throat
    • Wheezing or other difficulty breathing.


Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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