Herpes simplex virus (HSV) hepatitis is an uncommon cause of fulminant hepatic failure, seen mostly in immunocompromised patients. Conventional treatment modalities for inflammatory bowel disease (IBD), such as steroids and azathioprine, have been known to cause HSV hepatitis. However, the reported incidence of HSV hepatitis in IBD patients undergoing tumor necrosis factor (TNF)-α inhibitor therapy is very rare. In this case report, we describe a rare case of fulminant HSV hepatitis that developed in a patient with Crohn's disease after treatment with the TNF-α inhibitor, adalimumab.