Tianeptine is a clinically effective anti-depressant with the unusual profile of increasing 5-HT uptake, thereby decreasing the synaptic availability of 5-HT. In the social interaction test of anxiety in the rat, withdrawal from chronic diazepam treatment produced a significant anxiogenic response that was reversed by acute administration of tianeptine (2.5–10 mg/kg). These doses were without significant effect in the vehicle-treated rats. Exposure of rats to cat odour resulted in anxiogenic responses in the plus-maze and social interaction tests and in decreased exploration. These changes were not reversed by 5 days treatment with tianeptine (2.5–10 mg/kg). Thus, tianeptine may not he effective in all anxiety states, but could be particularly useful in treating patients withdrawn from benzodiazepines.