A 31-year-old woman had recurrent mild flare-ups of polymyositis for years. Fourteen days after low-dose methotrexate was added in an attempt to taper the corticosteroid, she began to feel abdominal and lower back pain, followed by generalized pustulosis, severe liver dysfunction, and disseminated intravascular coagulation. On the diagnosis of varicella-zoster virus (VZV) hepatitis, acyclovir, immune globulin and plasmapheresis were given with a favorable outcome. Physicians should be aware that VZV infection could complicate severe hepatitis in immuno-suppressed patients.