This study was designed to evaluate possible side effects on liver and kidney functions and haematological indices, associated with long-term intravenous (IV) administration of flunixin meglumine in healthy dogs. For this purpose, 12 dogs were divided into 2 equal groups. Group 1 was intravenously given flunixin meglumine at the dose of 1.1 mg/kg/day for 5 days and g-roup 11 received 2.2 mg/kg/day IV for 5 days. Blood samples were withdrawn before treatment (day 0), 2 h post injection on each day of treatment and one day after the last injection for biochemical (glucose, sodium-Na, potassium-K, chloride-Cl, creatinine, urea, alkaline phosphatase-AP, alanine amino transferase-ALT and total protein) and haematological (bleeding time, coagulation time, red blood cell, white blood cell, platelet count, differential leukocyte count, haematocrit and haemoglobin) analyses. Faecal and urine samples were collected on the same days as blood samples for the presence of any abnormalities. The results revealed a significant increase in bleeding (P < 0.001) and coagulation time (P < 0.001) and a decrease in platelet count (P < 0.001) in both groups. There was also a significant increase in the concentration of Na and Cl in group 1 and an elevation in AP (P < 0.00 07 ALT (P < 0.001) and glucose (P < 0.001) in group II. Blood in urine and faeces was also evident in both groups. The results may suggest that the dose of 1.1 mg/kg IV for 5 d does not cause any significant side effects provided that no bleeding disorder exists. and the dose of 2.2 mg/kg IV for 5 d should not exceed 3 d as liver enzymes began to increase significantly afterwards.