The incidence of inflammatory bowel disease with its two main manifestations, colitis ulcerosa and Crohn's disease, is rising globally year after year. There is still a tremendous need to study the underlying pathomechanisms and a well-established tool in order to better understand the disease are colitis models in rodents. Since the concept of the 3Rs was proposed by Russell and Burch, this would include pain medication in animal models of intestinal inflammation as a reduction of suffering. This review argues against pain medication because the administration of pain medication in its current form has an impact on the inflammatory process and the immune response, thus falsifying the results and the reproducibility and therefore leading to misconceptions.