The authors report a case of acute methemoglobinemia in a patient treated with naproxen for the common cold. A 42-year-old Asian woman began taking naproxen sodium and methocarbamol formylagia, chills, and coughing. On the day prior to her emergency department (ED) admission,the patient was taking lorazepam, trazodon, and paroxetine in addition to the naproxen and methocarbamol prescribed for the cold symptoms, and she also ingested approximately 300 mL of 20% alcohol. Upon awakening the next morning, the patient experienced dyspnea and dizziness. At the hospital, she was diagnosed with severe methemoglobinemia. After initiation of methylene blue therapy, the patient's symptoms improved substantially and her serum methemoglobin levels decreased. After 10 days in the hospital, the patient was discharged without any complications.Naproxen is known to cause oxidative stress. Alcohol is known to reduce G6PD activity, and thus it is hypothesized that the administration of naproxen in an alcohol-dependent patient caused methemoglobinemia.