Anemia is a disease condition associated with reduced blood levels of red blood cells, hemoglobin, hematocrit and alteration other hematological indices, leading to decreased ability to transport oxygen in the body. It can be precipitated by many risk factors that may occur independently or concurrently. Tradomedicinal practice claims to treat anemia by use of herbal plants which are readily available, accessible and affordable when compared to pharmaceutical drugs. This work therefore sought to pharmacologically study the anti-anemic activity of a spice plant (Piper guineense) on phenylhydrazine-induced anemia in wistar rats. This was done by randomizing thirty adult male wistar rats into six groups (1-6) of five animals per group, measuring their hematological indices before (at day 0) and after (at day 7, 14 and 21) induction of anemia with phenylhydrazine (40 mg/kg, i.p.). Groups 1, 2 and 3 respectively served as normal, negative and positive control, while groups 4, 5 and 6 received Piper guineense leaf extract at 125, 250 and 500 mg/kg respectively. The results of this study shows that Piper guineense leaf extract particularly at medium and high doses, and with respect to negative control, ameliorates phenylhydrazine-induced alterations on hematological indices, by producing significant (p<0.05) lesser percentage decrease in blood levels red blood cells, hemoglobin and hematocrit, as well as exhibiting significant (p<0.05) lesser percentage increase in blood levels of other hematological indices analysed in this study. The results also indicate that Piper guineense leaf extract when compared to positive control, produces insignificant (p>0.05) activity, particularly at days 14 and 21. This study provides a robust scientific validation of tradomedicinal claim on Piper guineense leaf as anti-anemic agent, therefore recommends further studies that will unveil the bioactive principle(s) and the molecular mechanism/pathway responsible for the observed activity.