We determined plasma activity of the isoenzymes of beta-hexosaminidase (Hex) in 151 patients with cerebral infarction, since earlier findings have shown a relation between Hex isoenzymes and risk factors for vascular disease in normal subjects. Compared with 206 control subjects, an elevated level of plasma Hex isoenzymes was found in patients with cerebral infarction, particularly females. However, there was no relation to the clinical subtypes of diagnosis or to the presence of any risk factors for vascular disease, such as carotid artery stenosis, major potential cardio-embolic risk factors on echocardiography, hypertension, heart disease, diabetes mellitus or tobacco smoking. Instead, our findings indicate that Hex isoenzymes in patients with cerebral infarction are more influenced by the level of serum aspartate aminotransferase and blood glucose. The main conclusion is that the liver function as reflected by the level of liver enzymes and glucose metabolism are the major determinants of Hex isoenzymes in plasma.