Skip to main content




What is metronidazole?

Metronidazole (also called Flagyl®) is a medicine used to treat infections. Metronidazole is available in these forms taken by mouth:

  • a 250-mg round, white tablet
  • a 50 mg/ml pink liquid suspension

Metronidazole is also available as a clear liquid given by vein.

How to take and store metronidazole

  • Take this medicine with or without food. If you have stomach upset, take metronidazole with food.
  • Shake the liquid suspension well before you take it. Use a medicine cup or an oral syringe to measure your dose to make sure you are taking the correct amount.
  • Store the liquid suspension in the refrigerator.
  • Store metronidazole tablets at room temperature in a dry place.
  • Discard the liquid suspension after 30 days or when the date on the label expires.

Possible side effects of metronidazole

  • Nausea, vomiting
  • Loss of appetite
  • Metallic taste
  • Headache
  • Diarrhea
  • Feeling dizzy

Tell your doctor right away if you have any of the following side effects:

  • Skin rash, hives, itching
  • Trouble breathing or swallowing
  • Unexplained sore throat or fever
  • Joint pain
  • Tingling, pain, or weakness in the hands or feet

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse, or pharmacist at 595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833), and press 0 once the call is connected.

Special instructions for metronidazole

  • Take all doses of this medicine, even if you begin to feel better before all doses are taken.
  • You should not consume any alcohol during metronidazole therapy and for one (1) day afterward. Alcohol is found in most over-the-counter cough and cold medicines.
  • Let your doctor know if you have had seizures or if you have numbness or tingling in your hands or feet.
  • Let your doctor or dentist know you are taking metronidazole before you have surgery requiring general anesthesia.
  • Metronidazole may turn your urine a reddish-brown color. This is normal.
  • This medicine may cause you to feel dizzy. Be careful when driving or using machinery.
  • Metronidazole may affect the way other medicines work, and other medicines can affect the way metronidazole works. These include:
    • Warfarin (Coumadin®)
    • Phenytoin (Dilantin®)
    • Phenobarbital
    • Cimetidine (Tagamet®)
    • Medicines containing alcohol.
  • Always tell your doctor if you are taking these medicines or if you start taking any new medicine while taking metronidazole.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).