Synthetic manganese-porphyrin complexes have been documented to act as scavengers for oxidative species such as peroxynitrite, superoxide, and hydrogen peroxide. EUK 134 is a salen-manganese complex that has been modified to increase its catalase activity while retaining SOD activity. EUK 134 is a salen-manganese complex that has been modified to increase its catalase activity while retaining SOD activity. EUK 134 consumes hydrogen peroxide with an initial reaction rate of 234 µM/min in vitro. ¹ EUK 134 is protective in a rat stroke model, employing middle cerebral artery ligation. At 2.5 mg/kg, rats treated with EUK 134 showed reduced infarct volume by more than 80%. EUK 134 at 10 mg/kg also significantly attenuates brain damage in rats following systemic administration of kainic acid. ²