The 2018 Wolfson Haldane Lecture was delivered by Professor Dame Nancy Rothwell and introduced by Professor Philomen Probert. Stroke is the third greatest killer and causes massive disability, yet there are few effective treatments. It is caused by a disruption of blood flow to part of the brain resulting in a catastrophic cascade and death of vital brain cells (neurones). We showed that inflammation, not commonly associated with brain disease, is a major factor in brain damage caused by a stroke and may also contribute to the devastating consequences of brain injury, haemorrhage and dementias. We have identified a key mediator of the inflammatory processes in stroke, a protein called interleukin-1 (IL-1). We have identified cell sources of IL-1, know it acts in the brain and in the rest of the body and have completed an early clinical trial of an IL-1 blocker in stroke and brain haemorrhage patients. These findings, plans and hopes for the future will be discussed. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/