Seventy percent ethanol, which was found to be the appropriate solvent for extraction of S. Collins I a eye roots (Kong) and less hazardous for the calves than methanol, was used as the extracting solvent and a negative control in the in vivo test. The effect of S.collinsiae extract on the percentage of attached ticks left on infested calf skin during 6 day after the treatment was demonstrated in Table 2. The S.collinsiae extract at 250 mg/ml concertration could reduce the attached ticks on the calf skin better than the control but less than flumethrin. There was a significant reduction of attached ticks after the treatment with S.collinsiae extract and flumethrin compared to the negative control. No side effect was found on calves during the experiment.