Introduction: Up to 40% of primary intracerebral hemorrhages (ICHs) expand within the first 24 hours (natural history). The authors aimed to study the safety and preliminary efficacy of epsilon-aminocaproic acid (EACA) in halting ICH enlargement. Methods: Consecutive patients with hematoma volumes ranging from 5 to 80 mL were recruited within 12 hours of ICH onset. A total of 5 g EACA was infused during 1 hour and then 1 g/hour for 23 hours. Hematoma volume was compared onbaseline, and 24-48-hour brain imaging. Consecutive untreated patients underwent the same imaging protocol. Results: Three of the first five patients treated had HE >33% of their baseline volume. HE occurred in two of the nine untreated patients. The 80% confidence interval for HE in the treated patients was 32-88%. No thrombotic or other serious adverse events were attributed to EACA. Conclusion: It is unlikely that the rate of HE in patients given EACA within 12 hours of ICH is less than the natural history rate, although this treatment appears to be safe.