The effect of an aqueous leaf extract of Ocimum gratissimum
(Linn), on haematological and biochemical indices in rabbits was studied. Increasing doses (0.4, 0.8 and 1.6 gkg-1
body weight) of the extract were administered orally to different groups of rabbits for a period of 4 weeks. Significant (P<0.05) decreases in the level of haemoglobin (Hb), packed cell volume (PCV), red blood cells (RBC) and white blood cells (WBC) were observed. The extract significantly (P<0.05, 0.005 and 0.01) reduced the activities of the liver enzymes, alanine aminotransamine (ALT), aspartate aminotransaminase (ASAT) and alkaline phosphatase (ALP). The decreases were dose dependent. There were clinical signs of loss of appetite and general malaise.