A 52-year-old women, suffering from generalized pruritus due to intrahepatic and common hepatic duct stones, was treated with astemizole, 30mg daily. Sixty one days later, convulsions and syncope developed suddenly during hospitalization. She had no history of arrhythmia, heart disease, electrolytes imbalance, or CNS disorders. As another case, a 44-year-old man suffering from pruritus due to liver cirrhosis, was treated with astemizole, 30mg daily. Thirty two days later, palpitations and syncope also developed suddenly during hospitalization. He was diagnosed liver cirrhosis, 3 years ago and there was no history of arrhythmia, heart disease, electrolytes imbalance, or CNS disorders. Administration of astemizole was stopped immediately. The laboratory investigations revealed the normal range of serum potassium, calcium and magnesium in both cases. The ECG finding showed the prolongation of QTc interval, frequent VPCs and intermittent polymorphic drugs. On 1st and 3rd day, after discontinue of astemisole, the ECG abnormalities disappeard. It is suggested that astemizole overdose can induce prolongation of QTc interval and torsade de pointes, especially in the patient with liver disease.