Metronidazole is a medication that treats infections. Metronidazole does not cause rosacea but rather treats it. Side effects may include nausea and diarrhea.

Metronidazole targets the bacteria that cause rosacea. A 2021 studyTrusted Source found that topical 0.75% metronidazole gel reduced the inflammatory lesions of rosacea with twice daily application.

Rosacea is an inflammatory skin condition that causesTrusted Source symptoms such as:

  • facial discoloration or flushing
  • rashes on the face, particularly around the nose and cheeks with pus-filled bumps
  • tingling or burning of the skin
  • sore, itchy eyes
  • blood vessels appearing on the skin
  • skin thickening, making the skin look swollen, discolored, and bulbous

Treatments can keep it under control, including:

  • topical treatments, such as gels or creams that constrict blood vessels or eliminate bacteria and parasites
  • oral medications such as antibiotics
  • eyedrops that help with eye irritation
  • laser therapy to remove excess tissue and shrink blood vessels
  • surgery to remove thickened skin

Metronidazole oral tablets also have a boxed warning. This is the most serious warning from the Food and Drug Administration (FDA), indicating the effects of the medication may be dangerous. Previous studies on the medication have found it to be carcinogenic, causingTrusted Source tumors in mice and rats.

However, animal studies use very large doses. Although this is a warning to consider when starting a medication, it may still be an option if a healthcare professional determines the drug to be the best treatment.

A person should thoroughly discuss the most suitable rosacea treatments with their doctor.