Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in populations and their side effects are well known. Acute kidney injury (AKI) can occur with any class of NSAIDs. A patient with diabetic nephropathy was prescribed tablet diclofenac 50 mg thrice a day for his back pain. Use of diclofenac worsened his plasma creatinine, urea nitrogen (BUN) and other tests about kidney functions. Following the deranged report, his medications including diclofenac were stopped. After one week, all the values dropped back to the previous range observed at his outpatient follow-up.