OBJECTIVES: To explore the possibility of international normalized ratio(INR),drug - warfarin interactions exaggerated intracerebral hemorrhage. METHODS: This is an observational study. Patients who had diagnoses of intracranial hemorrhage (ICH,ICD-9-CM codes 430, 431, 432.0, 432.1, 432.9) from January 2004 to December 2009 were retrieved from the claim database of a medical center in southern Taiwan. We reviewed medical records to identify the possible relationship with suspected risk factors, drug-warfarin interactions and ICH. Patients who were not taking warfarin at the time of hemorrhage and traumatic ICH were excluded. Potential drug interactions were defined according to on-line drug interaction database of Lexi-Interact TM. Data were analyzed by multivariate logistic modeling. RESULTS: During the study period, 24 patients were defined as ICH while patients were receiving warfarin. Forty-five percent of patients had an INR value>3.0 at admission to hospital and 25% were exceeded 5.0. The potential drug-warfarin interaction were antiplatelets (41.6%), allopurinol(16.6%),amiodarone (8.3%), ,NSAID(16.6%), others (16.6%).which may increased the bleeding risk . Five patients of 24 patients were died within two weeks. No correlation between the fatal cases and their gender, age, INR value, smoking, alcohol and comorbid diseases was founded. CONCLUSIONS: Although no correlation between drug-warfarin interaction, INR and ICH was found in this study, physicians should still need to inform patients, who are taking warfarin, to concern the potential interactions between herbs and over-the–counter medicines.