OBJECTIVE： To study the hypnotic and sedative effects of water extract of Sugmel-3 decoction on mice and its effects on insomnia of insomnia model rats. METHODS： The mice were randomly divided into blank group （normal saline， 2    mL/100 g）， positive control group （alprazolam， 0.15 mg/kg）， water extract of Sugmel-3 decoction high-dose and low-dose groups （90.0， 45.0 mg/kg， calculated by crude drug， similarly hereinafter）， with 12 mice in each group. Each group was given relevant medicine intragastrically once a day， for consecutive 5 days. The change of spontaneous activity （activity time and the number of standing）， the effects of hypnotic dose of pentobarbital sodium （50 mg/kg） on latency and duration of sleep were observed in mice. Insomnia rat model was induced by intraperitoneal injection of para-chlorophenylalanine. Model rats were randomly divided into model group （normal saline， 2 mL/100 g）， positive control group （alprazolam， 0.09 mg/kg）， water extract of Sugmel-3 decoction high-dose and low-dose groups （108.0， 54.0 mg/kg）， with 10 rats in each group. Other 10 normal rats were included in blank group （normal saline， 2 mL/100 g）. Other groups were given relevant medicine intragastrically once a day， and then sacrificed after consecutive administration of 7 d. ELISA assay was used to detect the contents of 5-HT， GABA， IL-1β， SOD and MDA in cerebral tissue of rats. RESULTS： In the experiment of sedation and hypnosis， compared with blank group， the activity time and the number of standings of mice in other groups were decreased significantly （P＜0.05 or P＜0.01）， sleep latency of mice was shortened significantly in water extract of Sugmel-3 decoction high-dosage group and positive control group （P＜0.05 or P＜0.01）. The sleep duration of mice was prolonged significantly in water extract high-dose group of Sugmel-3 decoction （P＜0.05）. In the experiment of hypnotic mechanism， compared with blank group， the contents of 5-HT， GABA and SOD in cerebral tissue of rats were decreased significantly in model group （P＜0.05）， the contents of IL-1β and MDA were increased significantly （P＜0.05）. Compared with model group， the content of 5-HT of rats was increased significantly in positive control group， water extract of Sugmel-3 decoction high-dose and low-dose group （P＜0.05 or P＜0.01）. The contents of GABA and SOD in cerebral tissue of rats were increased significantly in water extract of Sugmel-3 decoction high-dose group and positive control group （P＜0.05 or P＜0.01）. The content of IL-1β of rats in water extract of Sugmel-3 decoction high-dose and low-dose group were decreased significantly （P＜0.05）， the others indexes differences were not statistically significant （P＞0.05）. CONCLUSIONS： The water extract of Sugmel-3 decoction has good sedative and hypnotic effects， and its hypnotic mechanism may be related to the regulation of level of 5-HT and GABA in central neurotransmitters and the cytokine IL-1β.