What is metronidazole?

An antibiotic.: Metronidazole (flagyl) is the generic name for an antimicrobial medicine that targets certain anaerobic bacteria, amoeba, and protozoa. It most commonly comes as an oral pill, and is indicated for use in a wide variety of conditions such as pelvic inflammatory disease, bacterial vaginosis, c. Diff colitis, among many others.

It's an antibiotic: Metronidazole is an antibiotic for treating protozoans like Entamoeba, Giardia, and Trichomonas; and bacteria like Bacteroides, Fusobacterium, peptostreptococci, Clostridium, Gardnerella, and Helicobacter. Topical (put on the skin surface) metronidazole is a treatment for rosacea (a facial rash disorder).