Reversal learning, a form of cognitive flexibility disrupted in many brain disorders, involves switching from one response to another when the reward contingencies of the responses are reversed. The hippocampus, especially the ventral hippocampus (VH), connects to fronto-striatal circuits regulating reversal learning. Previous studies reported that hippocampal lesions impaired, whereas chemogenetic activation of VH facilitated, reversal learning acquisition in animal models. However, there is limited evidence on how VH activity affects distinct stages of reversal learning. Therefore, we examined how VH functional inhibition or disinhibition, by infusion of a GABAA receptor agonist (muscimol) and antagonist (picrotoxin), affects repeated reversal learning and reversal learning acquisition in rats performing a two-lever discrimination task. To study repeated reversals, rats were trained to acquire a spatial discrimination (press left or right lever) followed by four reversals, to achieve stable performance levels. Then, the impact of VH muscimol, picrotoxin and saline infusions on repeated reversals was compared within-subjects. To study reversal learning acquisition, we examined the impact of VH functional inhibition and disinhibition on spatial discrimination and three reversals in a between-subjects design. VH functional inhibition, but not disinhibition, impaired repeated reversal learning, indicating that repeated reversal learning requires VH activity, but not balanced levels of VH activity. In contrast, VH disinhibition, but not inhibition, impaired expression of the previous response during reminder trials preceding reversal trials, suggesting such expression does not require VH activity but may be disrupted by aberrant activation of projection sites. Our study of reversal learning acquisition is currently ongoing.