The International Stroke Trial (IST) analyzed data from 17,398 patients with acute ischemic stroke to explore the relationship between systolic blood pressure (SBP) and clinical outcomes. A U-shaped relationship was found between baseline SBP and both early death and late death or dependency: early death increased by 17.9% for every 10 mm Hg below 150 mm Hg, and by 3.8% for every 10 mm Hg above 150 mm Hg. Recurrent ischemic stroke within 14 days increased by 4.2% for every 10 mm Hg increase in SBP. Death from presumed cerebral edema was independently associated with high SBP. Low SBP was associated with severe stroke and increased deaths from coronary heart disease. Both high and low blood pressure were independent prognostic factors for poor outcome. High blood pressure was linked to early recurrence and death from cerebral edema, while low blood pressure was associated with early fatal coronary events. Symptomatic intracranial hemorrhage was independent of SBP. The study found that blood pressure management during acute stroke remains unclear, with no reliable evidence from randomized trials. The results suggest that both high and low blood pressure levels are associated with worse outcomes, highlighting the need for further research on blood pressure management in acute stroke patients.The International Stroke Trial (IST) analyzed data from 17,398 patients with acute ischemic stroke to explore the relationship between systolic blood pressure (SBP) and clinical outcomes. A U-shaped relationship was found between baseline SBP and both early death and late death or dependency: early death increased by 17.9% for every 10 mm Hg below 150 mm Hg, and by 3.8% for every 10 mm Hg above 150 mm Hg. Recurrent ischemic stroke within 14 days increased by 4.2% for every 10 mm Hg increase in SBP. Death from presumed cerebral edema was independently associated with high SBP. Low SBP was associated with severe stroke and increased deaths from coronary heart disease. Both high and low blood pressure were independent prognostic factors for poor outcome. High blood pressure was linked to early recurrence and death from cerebral edema, while low blood pressure was associated with early fatal coronary events. Symptomatic intracranial hemorrhage was independent of SBP. The study found that blood pressure management during acute stroke remains unclear, with no reliable evidence from randomized trials. The results suggest that both high and low blood pressure levels are associated with worse outcomes, highlighting the need for further research on blood pressure management in acute stroke patients.