Despite the fact that the incidence of renal complications due to non-steroidal antiinflammatory drugs (NSAID) is low when compared to their massive utilisation, signs of deteriorating renal function due to the use of NSAID seem to have increased in recent years. 2. Most renal complications are reversed when NSAID are withdrawn. 3. Clinicians should always search for signs of risk situations (decreased effective plasma volume, preexisting renal failure, age, etc.). In these situations, the hydration state should be checked before, and blood creatinine after, the start of therapy.