The world’s largest ever clinical trial looking at whether taking aspirin every day stops some of the most common cancers coming back launched on 22 October 2015. The Add-Aspirin phase III trial, the largest of its kind and funded by the NIHR HTA Programme and Cancer Research UK, aims to find out if taking aspirin every day for five years can stop or delay cancers that have been caught and treated at an early stage from returning. It will also study how the drug might do this. The study will recruit 11,000 patients who have recently had, or are having, treatment for bowel, breast, oesophagus (food pipe), prostate or stomach cancer. It will be open at more than 100 centres across the UK and will run for up to 12 years. Details of the trial and the background to it are available on the NIHR website.