The present study was undertaken to investigate the effect of paroxetine, a selective serotonin reuptake inhibitor (SSRI). on marble-burying behavior in mice in comparison with those of fluvoamine and clomipramine. Marble-burying test is extensively used as an animal model for obsessive/compulsive disorder A significant inhibition in marble-burying behavior was observed with paroxetine, at a dose of,10 mg/kg. The earlier SSRI, fluvoxamine, also significantly inhibited marble-burying behavior at a dose of 30 mg/kg. Although clomipramine. a tricyclic antidepressant, caused an inhibition in marble-burying behavior, a high dose of 100 mg/kg was needed to show a significant effect. On the other hand. all the drugs used in the present study showed no significant changes in spontaneous locomotor activity at doses inhibiting marble-burying behavior. In conclusion, it was confirnied that paroxetine has a potent inhibitory effect on marble-burying behavior in mice, and could have a similar antiobsessive/ anticompulsive activity in hunan beings. (c) 2005 Prous Science. All rights reserved.