ObjectivesThe aim of this study was to assess the distribution on the general characteristics and risk factors study according to onset time in acute ischemic stroke patients.MethodsWe studied hospitalized patients within 4 wks after the onset of stroke who were admitted at the Department of Internal Medicine at Kyunghee oriental medical center, Kyunghee university East-West Neo medical center, Kyungwon university Songpa oriental medical center, Kyungwon university Incheon oriental medical center, Dongguk university Ilsan oriental medical center from April 2007 to August 2008. The 24-hour day was divided in quartiles(6:00 to 12:00, 12:00 to 18:00, 18:00 to 24:00 and 24:00 to 6:00). We analyzed the general characteristics and risk factors according to onset time in acute ischemic stroke patients.Results468 subjects were included into the final analysis.1. The greatest time period for ischemic stroke onset is between 6:00 and 12:00. It demonstrated a 50% excess risk between 6:00 and 12:00.2. On the demographic variables of the patients, the rate of hypertension were significantly higher 18:00 to 24:00 than 24:00 to 6:00.3. There was no significant difference of Stroke type, Sasang constitution, Life style between groups.4. According to the blood test, high density lipoprotein cholesterol were significantly higher 24:00 to 6:00 and lower 12:00 to 18:00 than other groups.5. The patients diagnosed as metabolic syndrome were significantly higher 12:00 to 18:00 and lower 24:00 to 6:00.6. Hypertension, coffee drinking habit showed close relationship with patients whose stroke occurred during awake in multivariate analysis.ConclusionsThe above results showed that the overall tendency of acute stage cerebral infarction patients varied according to their onset time. According to the analysis, the rate of hypertension were significantly higher 18:00 to 24:00 than 24:00 to 6:00 and hypertension, coffee drinking showed close relationship with patients whose stroke occurred during awake in multivariate analysis. These results can be utilized in the future as a basis material.