Abstract
Ustekinumab is a first-line drug for Crohn's disease. However, little is known about its potential adverse effects on renal function. We present the case of a 42-year-old man with Crohn's disease who developed chronic renal dysfunction during ustekinumab treatment, which resolved after discontinuing ustekinumab. The findings underscore the importance of close monitoring of renal function in patients receiving ustekinumab, particularly those with preexisting kidney disease or risk factors for renal dysfunction.