Please consult your physician before taking any medication. Flagyl 250mg 30 Tabs Generic Name: metronidazole (me troe NI da zole) Brand Names: Flagyl, Flagyl 375, Flagyl ER, Protostat What is Flagyl (metronidazole)? Metronidazole is an antibiotic. It fights bacteria in your body. Metronidazole is used to treat bacterial infections of the vagina, stomach, skin, joints, and respiratory tract. This medication will not treat a vaginal yeast infection. Metronidazole may also be used for purposes other than those listed in this medication guide.