This research work evaluated the effects of Psidium guajava leaf extract on differential white blood cell count, % Packed Cell Volume(PCV) and Hemoglobin (Hb) concentration in acute -induced inflamed wistar rats. The study involved the use of forty five rats (in two groups) and were each divided into various subgroups (5mg/kg, 10mg/kg, 15mg/kg of extract and aspirin and control groups), with average weight of 150-270g. The initial, inflamed, and treated values of rats paw volumes were taken and after inducing inflammation with egg albumin and after a period of administration of the extract and aspirin, the rats were sacrificed and blood samples were collected. The results obtained at the end of the experiment showed that there were differences in values (i.e. initial, inflamed and treated). There was an increase in %PCV, WBC, Hb concentration after administration of extract and aspirin which led to a decrease in inflammatory effect. The effect may be due to the anti-inflammatory components present in P. guajava leaf and stem bark extracts which not only inhibit the production of inflammatory mediators but equally have multiplier effects on acutely low hematologic parameters. Based on these results, it is clear that P. guajava extracts possess components that sustain prompt recovery of these hematologic parameters during inflammation, a possible mechanism of action of its anti-inflammatory effect on animals.