Abstract
Lactulose, a synthetic sugar not able to be digested and absorbed by human beings, is widely used to treat constipation and hepatic encephalopathy clinically. Through fermentation by the bacteria in the gastrointestinal tract, lactulose can produce considerable amount of hydrogen, which is protective for ischemic stroke as a unique antioxidant. We propose that lactulose can induce the production of endogenous hydrogen that in turn reduces oxidative stress and ameliorate the stroke damage in human beings.