Non-steroidal anti-inflammatory drugs (NSAID) are widely used in paediatric population because of their proven efficacy and excellent safety profile in a diverse range of clinical conditions. The paper reports a case of a 13-year-old boy who developed acute renal failure (ARF) induced by iv ketorolac given for pain management in the post-operatory course for appendicectomy, during a state of dehydration. This case report underlines that the use of NSAID in a volume depleted patient can lead to ARF via inhibition of renal prostaglandin synthesis and highlights the need to be aware of the effect of NSAID on volume depleted patients.