The antimalarial potential of the ethanolic extract of Clerodendrum violaceum leaves (13 mg/kg body weight) was investigated in mice infected with Plasmodium berghei. Haematological indices including the red blood cell indices, the white blood cell indices and platelet count were also evaluated on days 3, 8 and 14 after infection. Phytochemical screening revealed a predominance of alkaloids (3.68 %), and phenolics (2.78 %) in the extract. The extract suppressed parasitaemia following administration to infected mice by 92.3% on day 14 post-infection. The infected extracttreated animals had significantly higher (P<0.05) red blood cell count (RBC), packed cell volume (PCV), haemoglobin concentration (Hb), white blood cell count (WBC), and platelet count than the infected untreated animals. The results suggest that the extract possesses considerable antimalarial activity and may induce synthesis of red blood cells, white blood cells and platelets. These results support further studies on Clerodendrum violaceum leaf as a source of antimalarial remedy.