Sodium nitrite is widely used as preservatives in foods consumed by the public. Sodium nitrite can cause hypoxia by converting hemoglobin into methemoglobin. CA1 pyramidal neurons is one of the structures in the hippocampus are susceptible to hypoxic conditions. To prevent damage to the CA1 pyramidal neurons of the hippocampus, it takes a neuroprotective agent. Gotu kola (Centella asiatica) is one of the plants the apparently has a neuroprotective effect. Objective: This study aimed to determine the effect of ethanol extract of gotu kola (Centella asiatica) on the expression of Bax in the hippocampal CA1 pyramidal neurons rat (rattus novergicus) induced sub-acute sodium nitrite. Methods: This study used post test control group design that uses 14 blocks of biological materials stored are divided into 3 groups: control group (K) as much as 4 blocks, group 1 (P1) as much as 5 blocks, and the treatment group 2 ( P2) as much as 5 blocks. The observations were analyzed by one way ANOVA test. Results: There were differences in the number of Bax expression in hippocampal CA1 pyramidal neurons significant difference between the control group, treatment 1 and treatment 2 (P = 0.000). Bax expression in group P1 is higher than P2. Conclusion: The ethanol extract of leaves of gotu kola (Centella asiatica) decrease Bax expression in hippocampal CA1 pyramidal neurons rat (Rattus norvegicus) induced by sodium nitrite subacute. 
Keywords: Centella asiatica, Sodium Nitrite, Bax Expression, Hippocampus CA1 Pyramidal Neuron.