The behavioural effects of the beta-carboline FG 7142 were investigated in the social interaction test of anxiety and the holeboard test of exploration and locomotor activity. FG 7142 (5-20 mg/kg) produced a significant decrease in the time spent in social interaction by pairs of rats, without an accompanying decrease in motor activity. This anxiogenic effect was highly correlated with the plasma concentrations of FG 7142 for the rats receiving 5 and 10 mg/kg doses, but not for those receiving the 20 mg/kg dose. In the holeboard, FG 7142 had no effect on exploratory head-dipping at the doses tested, but selectively reduced locomotor activity and the number of rears. The profile of FG 7142 in these tests is compared with those of the beta-carbolines, B-CCE and B-CCP.