Bentonite clay is widely distributed all over the world and it has been consistently used for its healing properties. In this study, the in vivo effect of natural Nigerian calcium bentonite clay on haematological parameters of wistar albino rat were investigated. The rats were fed for a total period of 28 days with varying concentrations of the bentonite clay. The haemoglobin count, packed cell volume, total white blood cell count, red blood cell count, platelet count, neutrophil and lymphocyte count were assayed. Test results showed that the bentonite had a lowering effect on haematological parameters studied in a concentration and time dependent manner with differences in concentration and time at 95 % confidence levels (P< 0.05). The highest decrease of 12.60 ± 0.36 vs control 14.35 ± 0.00 (g/dl) was obtained for Hb at the highest concentration of 0.07g at 28 days duration. PCV, WBC, RBC, platelet, neutrophil and lymphocyte analysis also showed highest decrease at 28 days duration at 0.07g/100g body weight. The results showed that using bentonite in small amounts for a short period of time had little effect. However, it is imperative that anyone intending to take large amounts of bentonite for long periods of time to undergo blood tests from time to time.
Keywords: Bentonite, Blood, Calcium, Haematological, Natural, Parameters.