Objective: To evaluate the antipiroplasmic activities of methanolic extract of Olea europaea (MOE) and acetonic extract of Acacia laeta (AAL) against Babesia and Theileria parasites in vitro and evaluate the chemotherapeutic effects of these extracts against Babesia (B.) microti in vivo. Methods: Fluorescence assay using SYBR Green 1 nucleic acid stain was used to detect inhibitory effects of the two extracts as well as the combination effects of the two extracts with diminazene aceturate and atovaquone on four Babesia species and Theileria equi in vitro while for in vivo experiments, 8-weekold female BALB/c mice were injected intraperitoneally with 1 × 10