Abstract: Daphnetin found in the Chinese herb Daphne giraldii Nitsche has been used as a non-narcotic analgesic in the clinic.When injected intraperitoneally in mice (100 mg/kg), its analgesic effects were potentiated by intraventricular injection of serotonin (5-HT, 20μg) or naradrenaline (NA, 1.25μg).The effect of daphnetin on the concentrations of noradrenaline (NA), dopamine (DA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), which are found in end-brain, interbrain and lower brain stem (including mid-brain, pons, medullary brain) in rats were determined.Experimental results indicate that daphnetin markedly increased the 5-HIAA content (133.3%) but did not affect the 5-HT content in lower brain stem. No other statistically significant changes of neurotransmitter had been observed.