Purpose: To investigate the anti-depressant activity of kaempferol, quercetin, kaempferol-3-O-β-Dglucose and quercetin-3-O-β-D-glucose isolated from Apocynum venetum (72.58 -90.24; 52.58 -70.24 s), 5-HIAA levels (940.8 -1244.7; 880.8 -1164.1 ng/g) and 5-HIAA/5-HT ratio (1.77 -4.76; 1.83 -4.16), but increased NE, DA and 5-HT levels (238.7 -405.7, 308.4 -528.1, 261.4 -531.9; 243.9 -423.6, 296.7 -534.9, 279.8 -481.4 ng/g) in FST and TST, compared with control group (146.18, 126.18 s; 1363.4, 1240 7.43, 6.16; 138.4, 235.4, 183.4 and 143.7, 218.6, 201.4 ng/g). The effects of the four flavonoids on the above indices were significant (p < 0.05) and positively related to their polarity. They had no CNS-stimulating effects in LAT. Conclusion:The anti-depressant activities of the four flavonoids are positively related to their polarity, and the mechanisms may be due to increased NE,