The effects of eltoprazine (DU 28853) on exploratory behavior and conspecific social attraction were examined in four experiments. Drug treatments somewhat enhanced three forms of exploratory behavior but decreased social attraction. The results indicate that eltoprazine, in sharp contrast to fluprazine, weakly ameliorates neophobic responses. Both eltoprazine and fluprazine seem to increase the aversiveness of encounters with other organisms, however. The latter effects may be mediated, in part at least, by some alteration in olfactory function.