Metronidazole is an antibiotic and antiprotozoal medication commonly used to treat various infections, including bacterial vaginosis, certain gastrointestinal infections, and some skin conditions. It works by inhibiting the growth of bacteria and parasites. Metronidazole can be administered orally, topically, or intravenously, depending on the type of infection being treated. It's important to follow a healthcare provider's instructions when using this medication, as it may have side effects and interactions with other drugs.