Ethnopharmacological relevance In traditional medicine, Astragalus mongholicus (AM) has been used for the treatment of general weakness, chronic illness, and to increase overall vitality. Aim of the study The present study investigated possible effects of the saponin fraction of AM on the central nervous system. Moreover, its effects on locomotor activity, anxiety, and hippocampal morphology were studied. Material and methods AM extract was tested for its effects on locomotor activity using the Moti-Test, for situational anxiety in the elevated plus maze, and for anticonvulsant activity against acute pentylenetetrazole (PTZ)-induced seizures and in the PTZ kindling model. Results It was shown that AM (50, 100, 200mg/kg) did not interfere with locomotor activity and situational anxiety as measured in the elevated plus maze. In these doses, AM significantly suppressed pentylenetetrazole (PTZ)-induced seizures (p <0.05). Its anticonvulsant efficacy was also evident against repeated PTZ seizures (p <0.05). This suggests potential therapeutic usefulness. After subchronic application, the number of cells in hippocampal CA1 was reduced, whilst the cell number in CA3 and hilus remained unaffected. Conclusions Doses of AM extract which did not interfere with locomotor acticity and situational anxiety appear to be useful in the treatment of convulsive disorders. The mechanisms underlying this effect on hippocampal morphology are not yet understood.