What Is Quercetin and How Does It Work?

Quercetin suggested uses include for seasonal allergies, prevention of diabetic cataracts, viral infections, cardiovascular disease, as adjunctive therapy in cancer, to treat chronic prostatitis, and interstitial cystitis.

  • Quercetin is possibly effective in the treatment of nonbacterial chronic prostatitis, and interstitial cystitis.
  • Other uses of quercetin are mainly derived from animal studies.

What Are Dosages of Quercetin?

Dosages of Quercetin:

Suggested Dosing

  • 400-500 mg orally three times daily
  • Prostatitis: 500 mg orally twice daily
  • Cancer: 420-1400 mg/m2 intravenous (IV) bolus once/week

Dosage Considerations – Should be Given as Follows:

  • See "Suggested Dosing"

What Are Side Effects Associated with Using Quercetin?

Common side effects of quercetin include:

  • Headache (oral use)
  • Numbness and tingling (oral use)
  • Shortness of breath (intravenous use)
  • Nausea and vomiting (intravenous use)
  • Kidney damage (intravenous use greater than 945 mg/m2)

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Quercetin?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

Quercetin has no known severe interactions with other drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

What Are Warnings and Precautions for Quercetin?


This medication contains quercetin. Do not take quercetin if you are allergic to quercetin or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Sophretin
  • meletin

Effects of Drug Abuse

  • None

Short-Term Effects

  • See "What Are Side Effects Associated with Using Quercetin?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Quercetin?"


  • None

Pregnancy and Lactation

  • There is no information available about the use of quercetin during pregnancy or while breastfeeding
  • Consult your doctor.
Medscape. Quercetin.

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