Extracts of Pterocarpus osun have been used as a histological dye but its hazard to health is yet to be fully determined and its use has been with care. The study determined the haematological changes in Wister rats fed with Pterocarpus osun. Concentrations ranging from 2.94g/kg, 5.88g/kg, 8.82g/kg, 11.76g/kg, 14.7g/kg, 17.64g/kg and 20.58g/kg were given orally to 35 rats in 5 groups daily for 28 days. Another group of 5 rats served as control. Blood samples were taken for full blood count and packed cell volume. The packed cell volume increased from 35±1.5% to 44±1.5%, while the total leukocyte count and differentials remained relatively within normal limits. The film appearance of the red blood cells was also normal. We conclude that chronic intakes of extracts of Pterocarpus osun did not show any evidence of toxicity in haematological indices, rather, it increased the PCV and with normal blood film appearance in Wistar rats.
