Thirty dehydrated diarrheic calves aged 2-45 days were used to study the effects of small volume intravenous 7.2% hypertonic saline and 6% dextran 70 solution in combination with alkalinising oral fluids and to compare this therapy with the large volume intravenous isotonic saline with alkalinising oral fluid treatment. This study included a total of 30 diarrhoeic dehydrated calves aged 2-45 days. After routine clinical and haematological examinations, the calves were allotted to two treatment groups. Isotonic saline solution (32 ml/kg, i.v.) with an oral electrolyte solution (22 ml/kg, p.o.) were administered to group I (control), and the combination of 7.2% hypertonic saline in 6% dextran 70 solutions (HSD) (4 ml/kg, i.v.) with an oral electrolyte solution (50 ml/kg, p.o.) were administered to group II (test). Additionally, an oral electrolyte solution (50 ml/kg, p.o.) was readministered to both groups at 12 h of the study. The clinical and haematological examinations of all calves were performed both before and after the treatment at the 1/2, 1, 2, 4, 12 and 24 h. The capillary refill time, peripheral pulse quality, dehydration degrees, mental status, haematocrit rates, haemoglobin and plasma values after treatment were found to be statistically different compared with the values before treatment. In comparison with group I, group II is observed to have shorter capillary refill time at 1, 4 and 12 h (P < 0.001) and better peripheral pulse quality at 1/2 (P < 0.05), 1, 2, 4 and 12 h (P < 0.001). Moreover, the degree of dehydration in group II, was significantly improved at 2 (P < 0.01), 4 and 12 h. Results of the study indicated that administration of low volumes of hypertonic sodium chloride and dextran 70 solution combinations with oral electrolyte solutions was concluded as quicker, practical, economical and most importantly an effective way for the treatment of dehydrated diarrhoeic calves.