In this study, the effects of crude extract from Areca catechu L. against the motility of newly-excysted juveniles (NEJs) O. viverrini on relative motility (RM) assay, Eggs per gram of feces and worm recovery. The liver flukes were divided into 2 experiment groups. Group 1 was control group (untreated) and group 2 were incubated in RPMI-1640 medium containing 200 µg/ml, 1 mg/ml, 5 mg/ml and 10 mg/ml of crude extract. After in vitro experiments, the RM values were evaluated after 0, 30, 60, 90, 120, 150 and 180 minutes incubation, using scoring under the stereomicroscopy. The results showed at 0 minute (before treatment), NEJs of O. viverrini has an active. The crude extract of A. catechu L. at all concentrations showed decreased rapidly of motility at 30 minutes incubation. The initial reduction of motility occurred at 30 minutes and more reduction at 60 minutes in A. catechu L extract at the concentration of 200 µg/ml, 1 mg/ml and 5 mg/ml. No motile parasites were observed when they were incubated with 10 mg/ml of crude extract for 150 and 180 minutes. Fecal egg outputs and worm burden form infected Syrian golden hamsters were significantly decreased in A. catechu L. extract treated group when compared to control group (infected with no treated). Results from the present study were suggested that A. catechu L. extract has the effects of inhibition of the liver fluke movement. Therefore, A. catechu L. may be further developed into herbals treatment for treating parasitic diseases.