On 14 September 2007, Belgium referred the matter to the EMEA under Article 31 of Directive 2001/ 83/ EC and asked the CHMP to give its opinion on whether the marketing authorisations for oral formulations of medicinal products containing norfloxacin in the treatment of acute or chronic complicated or uncomplicated pyelonephritis should be maintained, varied, suspended or withdrawn across the European Union following the re-assessment of norfloxacin benefit/ risk balance.