The present study was conducted to evaluate the alterations in oxidative stress parameters in dogs suffering from haemorrhagic gastroenteritis (HGE). Dogs presented with vomiting and diarrhoea were screened and fifteen animals with signs suggestive of HGE were included in the study. The oxidative stress parameters, serummalondialdehyde (MDA) level, total antioxidant status (TAS) and plasma glutathione peroxidase (GSH-Px) activity were studied. The values were compared with the values from six apparently healthy dogs. A significant increase was noticed in the mean values of serum MDA and TAS of diseased animals at the time of presentation when compared to healthy animals whereas the activity of plasma GSH-Px was found to be lower than in healthy dogs. Supplementation with N-acetyl cysteine @ 70 mg/kg or five days was found effective in managing the oxidative injury in the affected animals.