Introduction: Metronidazole is a nitroimidazole antimicrobial drug prescribed to treat infections caused by anaerobic bacteria and protozoa. Metronidazoleinduced encephalopathy ( MIE ) is a rare toxic encephalopathy caused by the drug metronidazole. The incidence of metronidazole-induced encephalopathy is unknown , although several previous studies have addressed metronidazole neurotoxicity. Metronidazole is efficacious in treating trichomoniasis, amebiasis, and giardiasis and in infections caused by obligate anaerobes and microaerophilic bacteria. It has been used for treatment of brain abscess, because anaerobic and microaerophilic bacteria constitute the most common pathogens. Metronidazole may produce neurologic side effects such as cerebellar syndrome, and encephalopathy in rare cases. Metronidazole is a commonly used antibiotic agent in various conditions such as anaerobic bacterial infections, protozoa infections (for example, giardiasis), Helicobacter associated gastritis, and hepatoencephalopathy.Previous reports have demonstrated that metronidazole toxicity may induce several neurologic side effects, including peripheralneuropathy, ataxic gait, dysarthria, convulsive seizures. MRI brain usually clinches the diagnosis.Metronidazole is commonly used in the treatment of brain abscess to cover anaerobes and MIEP can lead to irreversible neurologic sequelae.Therefore, MIEP should always be borne in mind when administering metronidazole for the treatment of cerebral abscess. Here, we report the case of a patient with reversible cerebellar dysfunction on magnetic resonance imaging, induced by prolonged administration of metronidazole for the treatment of infectious colitis.