Metronidazole belongs to the class of medicines known as antibiotics. It works by killing bacteria or preventing their growth. However, this medicine will not work for colds, flu, or other virus infections. This medicine is available only with your doctor's prescription. Metronidazole is used to treat infections of the reproductive system, gastrointestinal (GI) tract, skin, heart, bone, joint, lung, blood, nervous system, and other areas of the body. It is also used to treat certain sexually transmitted diseases (STDs). Metronidazole is primarily used to treat: bacterial vaginosis, pelvic inflammatory disease (along with other antibacterials like ceftriaxone), pseudomembranous colitis, aspiration pneumonia, rosacea (topical), fungating wounds (topical), intra-abdominal infections, lung abscess, periodontal disease, amoebiasis, oral infections, giardiasis. Metronidazole (Flagyl) is a medication that treats infections caused by bacteria or parasites. You can take this tablet or capsule by mouth. Metronidazole is a prescription antibiotic medication prescribed for the treatment of a variety of parasitic and bacterial infections of the vagina, gynecological area, skin, intra-abdominal cavity, blood, bone, joint, nervous system, and heart. Find patient medical information for Metronidazole (Flagyl, Likmez) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Metronidazole is an antibiotic that may be used to treat certain infections of the vagina, stomach, liver, skin, joints, brain and spinal cord, lungs, heart, or bloodstream.