ObjectiveTo explore the mechanism of Xiaoyaosan in alleviating lipopolysaccharide （LPS）-induced depressive-like behavior in mice based on the c-Jun N-terminal kinase （JNK） pathway. MethodAfter adaptive feeding， C57BL/6J mice were randomly divided into normal group， model group， minocycline group （intrabitoneal injection， 50 mg·kg-1）， fluoxetine group （intragastric administration， 2.6 mg·kg-1）， and low-， medium-， and high-dose Xiaoyaosan groups （intragastric administration，6.012 5， 12.025， and 24.050 g·kg-1）. After 14 days of administration， the model group and each administration group were intraperitoneally injected with 2 mg·kg-1 LPS， and the normal group was intraperitoneally injected with equal volume of normal saline. Depressive-like behavior in mice was assessed using the open field test and the elevated zero maze test. High-performance liquid chromatography （HPLC） was used to measure the levels of norepinephrine （NE） and epinephrine （E） in the mouse hippocampus. Enzyme-linked immunosorbent assay （ELISA） was performed to determine serum interleukin-1β （IL-1β） levels. Immunohistochemistry was used to measure the protein expression levels of ionized calcium-binding adapter molecule-1 （Iba-1）， c-Fos， and c-Jun. Real-time polymerase chain reaction （Real-time PCR） was used to measure mRNA expression levels of IL-1β， c-Jun， c-Fos， and JNK3 in the mouse hippocampus. Protein expression levels of JNK and phosphorylated （p）-JNK in the mouse hippocampus were measured using capillary protein automated protein expression analysis system （Western）. ResultCompared with the normal group， the model group exhibited significantly reduced central area residence time， crossing times， and travel distance in the open field （P<0.01）， significantly increased serum IL-1β levels （P<0.01）， significantly decreased NE and E levels （P<0.05）， upregulated mRNA expression of IL-1β， JNK3， and c-Fos， and increased protein expression of Iba-1， c-Fos， and c-Jun （P<0.05， P<0.01）. Compared with the model group， the Xiaoyaosan groups showed increased central area residence time and open arm residence time （P<0.05）， increased NE and E levels （P<0.01）， decreased mRNA expression of IL-1β， JNK3， c-Jun， and c-Fos， and decreased protein expression of Iba-1， c-Fos， JNK， and p-JNK （P<0.05， P<0.01）. The minocycline group and the fluoxetine group showed decreased mRNA expression of JNK3， c-Jun， and c-Fos （P<0.05， P<0.01）. The minocycline group showed decreased serum IL-1β and p-JNK protein expression （P<0.01）. The fluoxetine group exhibited increased NE and E levels and decreased c-Fos protein expression （P<0.01）. ConclusionXiaoyaosan can improve depressive-like behavior induced by LPS in mice， and its mechanism may be related to the inhibition of neuroinflammatory responses and the JNK pathway.