Alimentary mucositis is an important complication of chemotherapy and/or radiation therapy, with significant implications for prognosis, nutrition, quality of life, and cost of care.^[1] However, despite a significant amount of research, the clinical management of most patients with mucositis remains largely palliative. ^{[2] and [3]} Thus, there is an urgent need to better understand the pathogenesis of mucositis and to test promising new interventions based on this understanding. Animal models of mucositis are critical for such studies, aimed at identifying the best agents for evaluation in humans.

Bowen et al have prepared a well-written review that nicely summarizes the major animal models for oral and gastrointestinal mucositis. This group of investigators, led by Professor Keefe, is one of the worldwide leaders in mucositis research using animal models. The article also describes animal models developed by other leading groups under the direction of Professors Dorr, Hauer-Jensen, Howarth, and Sonis. Together the animal models developed by these and other groups have resulted in significant advances in our understanding of the pathogenesis of mucositis and the identification of promising therapeutic candidates.

However, as Henry Wadsworth Longfellow wrote, “Into each life some rain must fall.” Indeed, animal models for mucositis have limitations that prevent them from exactly reproducing the human condition. Due to the multifactorial nature of the pathophysiology of mucositis, replication in an animal model can be challenging. As a result, several interventions that were extremely promising in animal models have turned out to be ineffective when tested in humans. Thus, there is a need for constantly adapting the animal models to better represent patients with mucositis, in addition to modifying them based on evolving cancer therapy regimens.

Ultimately, the best research model for mucositis is the human.