AimTo investigate the relationship between serum homocysteine (Hcy) levels and stroke severity and subclassification in patients with acute cerebral infarction (ACI).MethodsThe serum Hcy levels in 423 patients with acute cerebral infarction were measured by enzyme-linked immunosorbent assay (ELISA), and they were grouped according to Chinese ischemic stroke subclassification (CISS) subclassification and National Institutes of Health Stroke Scale (NIHSS).The patients between all the subclassification and 179 healthy controls were compared.ResultsThe serum Hcy levels in ACI group were significantly higher than those in control group (18.07±10.23 μmol/L vs 7.40±3.48 μmol/L); The serum Hcy levels in light, medium, heavy stroke group were 16.76±6.37 μmol/L, 20.41±6.01 μmol/L, 24.48±6.29 μmol/L, and the difference of groups were statistically significant.No futher significant difference was found among different subclassification.ConclusionsThe serum Hcy levels increased in acute cerebral infarction, which is closely related with the occurrence of cerebral infarction, and can be used to be a indicator to determine the severity of ACI.No further significant difference was found among different subclassification.