A 92-year-old woman presented with severe acute haemorrhagic gastritis due to abuse of non-steroidal anti-inflammatory drugs (NSAIDs). She was treated with instillation of 150 ml 3% hydrogen peroxide (H2O2) every 2 h via a nasogastric tube. The copious amount of bright red blood through the nasogastric tube started to decline substantially after the first administration of H2O2 and continued to reveal clear material during the second and third instillation of H2O2. The total amount of H2O2 administered was 600 ml. No rebleeding and only a few flame-shaped intramucosal haemorrhages were observed on the following four consecutive daily endoscopic evaluations. These are promising observations which will have to be confirmed with respect to the safety and efficacy of H2O2 treatment by further controlled studies.