Two male patients aged 33 and 38 years with mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS)admitted in our hospital in 2016 and 2017 were reported.The main symptoms included abdominal pain and distension,numbness and weakness of the limbs.MRI showed mild ventriculomegaly with deepened sulcus and widened cerebral fissure,deepened bilateral cerebellar sulcus and the widened cleavage,atrophy of cerebellum and brainstem,and manifestations of acute cerebral infarction.Gene analysis showed mutation of mitochondrial DNA(mtDNA) A3243G.After definite diagnosis was made,patients reveived coenzyme Q10,ATP and vitamin supplements for improving circulation,and neurotrophic drugs for symptomatic treatment.The symptoms were slightly improved after treatment and two cases were followed-up as outpatients.