About ornidazolesa nitro imidazole derivative, antiprotozoal antibiotic,antimicrobial.smechanism of action of ornidazolesornidazole is a nitro imidazole which has 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 excerts cytotoxic action by damaging dna and other critical biomolecules. 3. dna helix destabilization &strand breakage has been observed. sindications for ornidazoles1.amoebiasis s2.giardiasis s3.trichomonas vaginitis s4.anaerobic bacterial infections s5.bacterial vaginosis