The ameliorative effect of salts, ascorbic acid olyphosphate and zinc oxide supplementation on heat stress was studied in adult buffaloes of either sex which were randomly divided into two groups of four animals each. Group I served as control and Group II was supplemented with sodium bicarbonate, potassium carbonate, ascorbic acid polyphosphate and zinc oxide. All the animals were exposed to two conditions of temperature and humidity: hot-dry and hot-humid in psychrometric chamber for 4 hours daily for 10 days. Blood was collected on days 1, 5 and 10 of treatment. The activities of enzymes catalase, superoxide dismutase (SOD) and concentrations of reduced glutathione (GSH), hormone cortisol and thiobarbituric acid (TBA) binding substances (lipid peroxidation) were estimated in serum. Significant decreasewas observed in activities of serum catalase and SOD. Serum GSH concentration decreased while serum concentrations of TBA binding substances and cortisol significantly increased in both groups which were subjected to heat stress. Dietary supplementation of ascorbate, zinc and electrolytes resulted in further decrease in the enzymes' activities where as the serum GSH increased at par to normal values. Serum concentrations ofTBA binding substances and cortisol were comparatively lower in supplemented group in both types of stress. Thus, supplementation of ascorbate and zinc in addition to electrolytes relieved the animals of oxidative stress.