EMA/CO is an active combination regimen for treatment of high risk metastatic gestational trophoblastic disease, but its life-threatening complications have hardly been reported. We present a case of high risk metastatic choriocarcinoma with a regimen incorporating EMA/CO. Unfortunately, a critical condition occurred to manifest pancytopenia, fever, ulcer of throat, vulvar and hand, as well as upper gastro-intestinal bleeding. The following conservative treatment attained a satisfactory outcome. To date 60 months after the initial treatment, there is no evidence of disease. Prevention and management of these complications would be discussed in this report.