Neurokinin-1, (NK1) receptor antagonists offer strong potential as anxiolytic drugs with few side effects. The use of the Mongolian gerbil for anxiety research offers advantages because gerbil NK1 receptors share a greater homology with human NK1 receptors than those of other rodents. Studies are needed to validate existing tests of anxiety for use with this species. This study examined the effects of two anxiolytics (buspirone and diazepam) and two anxiogenics (caffeine and FG142) on male and female gerbil behaviour in the black-white box (BWB). Diazepam was anxiolytic in males but not females. The anxiolytic effects of buspirone were apparent at the lower doses in both males and females. Higher doses resulted in sedative effects in both sexes. Caffeine produced mild anxiogenesis in females at the lowest dose, and in males at the highest dose. FG7142 was mildly anxiogenic in males and not at all in females. Findings are discussed in light of previous research. The gerbil BWB should not be used as a valid test of anxiety in its current form.