The present work explores suspicious consequence of low molecular weight glycosaminoglycan (LMW-GAG) on oxidative stress and cellular abnormalities in isoproterenol (ISO)-induced myocardial infarction in an experimental model. Group-III male Wistar rats (140 +/- 10 g) were administrated by ISO (85 mg ISO/ml subcutaneously (SC) injected at the last two days of a 2-week period). Group-IV rats were treated LMW-GAG plus ISO (300 microg/day per rat SC for 1 week followed by 85 mg/kg ISO on the end last two days of the 2 - weeks). Untreated control (Group-I) and LMW-GAG drug control (Group-II) were also included. Serum and tissue lactate dehydrogenase, aminotransferases, and creatine kinase activities were increased in ISO group, which were normalized by LMW-GAG pretreatment rats. Antioxidant enzymes - superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities and non-enzymatic enzyme reduced glutathione (GSH) were decreased in the ISO induced rats, and this was increased by LMW-GAG pretreatment. Increased level of thiobarbituric acid reactive substances (TBARS) in plasma and the heart of ISO treated rats; pre s.c. injected with LMW-GAG to ISO-induced rats decreased the levels of TBARS. Histological examination revealed that the ISO-induced deleterious changes in the heart tissues were offset by LMW-GAG treatment. LMW-GAG affords considerable protection to the tissues challenged by cardiotoxicity, evidenced by its correction and restoration of serum and tissue indices of injury, to normalcy.