The article presents the case report of a 45-year-old white man who became acutely ill with fever, chills, and nausea for 3 weeks. He had received cimetidine and naproxen for 6 weeks. A diagnosis of acute allergic interstitial nephritis was made and a renal biopsy was performed. It is stated that the case illustrates the importance of recognizing druginduced interstitial nephritis.