Anaphylactoid and/or anaphylactic reactions to fluoroquinolones are estimated to occur in 0.46-1.2/100,000 patients. A 49-year-old woman with a history of asthma was admitted for a presumed asthma exacerbation related to an infectious process. She was given levofloxacin and standard management for an acute exacerbation. On two occasions the patient's respiratory distress worsened, requiring intubation. The second reaction occurred immediately after levofloxacin administration and was accompanied by a marked cutaneous reaction. Levofloxacin was discontinued, and supportive care was provided. No further symptoms occurred. The patient later was found to have been started on levofloxacin before admission for a suspected upper respiratory infection.