Edaravone was originally developed as a potent free radical scavenger and has 
been widely used to treat cerebral infarction in Japan since 2001. Several free 
radical scavengers have been developed and some of them have progressed to 
clinical trials for the treatment of cerebral infarction. One such scavenger, 
edaravone, has been approved by the regulatory authority in Japan for the 
treatment of patients with cerebral infarction. Of particular interest is the 
ability of edaravone to diffuse into the central nervous system in various 
neurologic diseases. Aside from its hydroxyl radical scavenging effect, 
edaravone has been found to have beneficial effects on inflammation, matrix 
metalloproteinases, nitric oxide production and apoptotic cell death. 
Concordantly, edaravone has been found to have neuroprotective effects in a 
number of animal models of disease, including stroke, spinal cord injury, 
traumatic brain injury, neurodegenerative diseases and brain tumors. The proven 
safety of edaravone following 9 years of use as a free radical scavenger 
suggests that it may have potential for development into an effective treatment 
of multiple neurologic conditions in humans.