MPO and inflammatory bowel disease: 2011; Muthas et al. 2017). Clinical studies have shown that intestinal mucosal MPO activity can be used as an indicator of the severity of IBD (Hansberry et al. 2017; Colombo et al. 2018) and, in the faeces, as a marker of IBD activity. Animal experiments have shown that MPO activity is significantly increased in colonic inflammation (Yukitake et al. 2011), whereas treatment with Guchangzhixie-Pill alleviates this inflammation and decreases MPO activity (Yang et al. 2017). Thus, MPO activity can be used as a quantitative indicator of the degree of colonic inflammation (Yang et al. 2017).