About metronidazolesa nitroimidazole antibiotic, anti-infective, antiprotozoal,amebicide.smechanism of action of metronidazolesmetronidazole is nitro imidazoles which have broad spectrum cidal activity against protozoa and some anaerobic bacteria. its selective toxicity to anaerobic microbes involves 1. drug enters the cell by diffusion, 2. nitro group of drug is reduced by redox proteins present only in anaerobic organisms to reactive nitro radical which exerts cytotoxic action by damaging dna and other critical biomolecules. 3. dna helix destabilization & strand breakage has been observed.sindications for metronidazoles1.amoebiasis s2.giardiasis s3.trichomonas vaginitis s4.pseudo membranous enterocolitis s5.anaerobic bacterial infections after surgery, brain abscess, & endocarditis s6.helicobacter pylori infections s7.ulcerative gingivitis