Immune checkpoint inhibitors (ICPis) are a novel class of cancer treatment that have improved outcomes for a subset of cancer patients. They work by antagonizing important inhibitory immune pathways, thereby augmenting immune mediated anti-tumour responses. However, immune activation is not cancer specific and often results in activation of immune cells in non-cancer tissues resulting in off-target immune-mediated injury and organ dysfunction. Diarrhoea and gastrointestinal tract inflammation are common and sometimes serious side effects of ICPi therapy. Prompt recognition of gastrointestinal toxicity and in many cases rapid institution of anti-inflammatory and/or biological therapy is required to reverse these complications. Optimal management of organ specific complications frequently requires engagement with gastroenterologists to deliver improved outcomes for patients developing ICPi-induced enterocolitis. In this British Society of Gastroenterology (BSG) endorsed guidance document we have developed a consensus framework for the investigation and management of ICPi-induced enterocolitis.