The acaricidal effect on engorged ticks was evaluated using the AIT (Drummond et al. 1973). Ten Stemona root samples representing nine different species were accurately weighed (each 2.5 and 1.0 g) and separately extracted by sonication for 45 min with methanol (10 ml) at ambient temperature. Each extract (equivalent to 250 and 100 mg of plant sample/ml) was then filtered using a no.1 Whatman filter paper and stored in a closed vial. The groups of 10 adult ticks (four replicates for each concentration) were immersed in the solution for 3 min with gentle agitation. Methanol and flumethrin were used as negative and positive controls, respectively. Ticks were removed from the solutions, air dried at room temperature for 3 min, and placed in a glass bottle covered with muslin cloth. They were left at room temperature for 24 h and recorded for their mortality. Dead ticks were characterized by the loss of their motility and pedal reflex