Can Metronidazole Change Urine Color?
In our latest question and answer, the pharmacist discusses whether or not metronidazole (Flagyl) can change the color of your urine.

Question
Can metronidazole change your urine color? Mine is a darker color than usual.

Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist
Staff
Last updated Mar 27, 2025
Key points
- A common side effect of Flagyl (metronidazole) is a change in urine color.
Answer
Flagyl (metronidazole) is both an antibacterial as well as an antiprotozoal agent. One of the most common side effects of metronidazole is urine discoloration, which commonly manifests as a darker than usual color.
Metronidazole is commonly prescribed to treat many types of skin infections, lower respiratory tract infections, and vaginal infections. Because metronidazole is effective against a variety of pathogens, it is widely used both as monotherapy (i.e. alone) as well as in combination with other medications.
Metronidazole Side Effects
Common side effects of metronidazole include but are not limited to:
- Urine discoloration/dark urine
- Headache
- Diarrhea
- Metallic taste
- Nausea
- Upset stomach
Metronidazole can be taken with or without food but should never be taken with any type of ethanol (including alcoholic beverages and common cough medications). If ethanol-containing substances are ingested while taking metronidazole, side effects can be severe and include:
- Vomiting
- Nausea
- Headache
- Rapid heart rate
- Flushing
- Abdominal cramps
Ethanol-containing products should not be ingested for up to three days after completing a course of metronidazole to avoid these effects.
Final Words
Thanks again for your question!
Metronidazole is cleared fairly quickly from your system, so if you have noticed a change in urine color due to the medication, it should go back to its usual color within a day or two at the latest.
References
- Flagyl Prescribing Information, Pfizer
-
Dr. Brian Staiger, PharmD
- 9446 views