The aim of the present study was to investigate the effect of 2-hydroxy-4-methoxy benzoic acid isolated from the roots of Hemidesmus indicus on plasma glucose, plasma, erythrocyte and erythrocyte membrane lipid peroxidation and membrane-bound Ca2+ ATPase activity in streptozotocin-induced diabetic rats. In our study, diabetic rats had increased levels of blood glucose and lipid peroxidation in plasma, erythrocytes and erythrocyte membrane and decreased level of plasma insulin and decreased activity of low affinity Ca2+ ATPase in erythrocytes. Restoration of plasma insulin and glucose in diabetic rats indicates the effect of HMBA on insulin, glucose and lipid peroxidation. HMBA also restored diabetes-induced alterations in the activity of membrane-bound Ca2+ ATPase. Based on the results of this study it can be concluded that HMBA mediated normalization of membrane-bound ATPase in erythrocytes is due to improved glycemic control and antioxidant activity.