"... The results of the European Cooperative Acute Stroke Study III (ECASS III) ... (ClinicalTrials.gov number, NCT00153036), reported in this issue of the Journal, teach us many lessons, some medical and some political, and clearly provide powerful, persuasive evidence that is safe and effective for patients with acute stroke. … The rationale for ECASS III arose from a pooled analysis of several previous studies that had differing time windows for enrollment. ... Analyses from the resulting pooled sample suggested that thrombolytic therapy could be beneficial even when given more than 3 hours after the onset of symptoms, and ECASS III was designed to confirm this hypothesis. As the authors of this article point out, however, neither their results nor those of the previous pooled analysis suggest that the ideal window for acute thrombolytic therapy is 4.5 hours after the onset of a stroke, because we know that the potential for neurologic rescue declines monotonically with every passing minute. ... I like to pose this scenario to my trainees: a patient presents to you 30 minutes after the onset of a left hemispheric stroke; how long do you have to initiate thrombolytic therapy? The correct answer is 1 minute, not 2.5 hours, and ECASS III does not now justify an answer of 4 hours. From the moment the patient arrives at the door, every minute counts ..."