Eleven terpenes extracted from Cassia alata and Ocimum gratissimum leaves were screened for in vitro antimalarial activity against Plasmodium falciparum and for their binding affinity with haemin in ethylene Glycol-water 3:7 solvent. Nine terpenes have promising antimalarial activity with IC 50 values below 1µg/ml; two terpenes showed a good activity with IC 50 values below 4µg/ml. All the terpenes bind strongly with haemin as shown by variation of absorbance of the haemin at λ 600nm in UV-Visible spectrum.