BACKGROUND: Sedative and hypnotic drugs could cure insomnia in a dependent manner, and traditional Chinese medicine has some superiority in treating insomnia.OBJECTIVE: To observe the synergistic action of Yinao capsules with pentobarbital sodium in threshold and sub-threshold dosages in hypnosia and sedation.DESIGN: A completely randomized grouping design and control experiment.SETTING: Pharmacological laboratory, College of Pharmacy, Henan College of Traditional Chinese Medicine.MATERIALS: Totally 200 grade Ⅱ Kunming mice of 18 - 21 g, either male or female, were used. Yinao capsules, main ingredients of which were turtleback glue, thinleaf milkwort root, Chinese magnoliavine fruit,mythic fungus, tangshen, ginseng and grassleaf sweetflag rhizome, were offered by Chinese-American Huayi Pharmacy, Co.,Ltd. (ratified number: 040901); Kangnaoshuai capsules, main ingredients of which were prepared rehmannia root, tuber fleeceflower root, ginseng, membranous milkvetch root, thinleaf milkwort root, Fushen, grassleaf sweetflag rhizome, spine date seed, lecithin, barbary wolfberry fruit, pueraria root,vitamin E, etc., were produced by Shijiazhuang Siyao, Co.,Ltd. (ratified number: 040964); Pentobarbital sodium was produced by China Medicine (Group) Shanghai Chemical Reagent, Co,.Ltd. (Ratified number:030816). ZZ-6 mice spontaneous activity apparatus was produced by Chengdu Taimeng Science and Technology, Co.,Ltd.METHODS: The experiment was carried out in the Animal Experimental Center, Henan College of spontaneous activity of mice: Fifty mice were randomly divided into five groups with 10 mice in each group:Mice in the large, middle and small dosages of Yinao capsules groups were intragastrically infused with Yinao capsules suspension (1.36, 0.68, 0.34 g/kg); Those in the Kangnaoshuai capsules group were infused with Kangnaoshuai suspension (1.12 g/kg); Those in the control group were given physiologic saline of the same volume. The mice were administrated once a day for 7 days continuously, and they were placed into the mice spontaneous activity apparatus after 60 minutes from the last administration, the times of spontaneous activities and the times of arising within 10 minutes were recorded after adaptation for 5 minutes.mice were randomly divided into 5 groups as above-mentioned with 14 mice in each group, and they were treated the same as above. They were intraperitoneally injected with 50 mg/kg pentobarbital sodium after 60 minutes from the last administration, then conditions of falling asleep were observed. The disappearance of righting reflex was taken as the index of falling asleep, the latency of falling asleep was the duration from intraperitoneal injection of pentobarbital sodium to fall asleep, the sleeping time was from falling asleep to sodium of sub-threshold dosage: Eighty mice were randomly divided into 5 groups as above-mentioned with 16 mice in each group, and they were treated the same as above. They were intraperitoneally injected with 27 mg/kg pentobarbital sodium after 60 minutes from the last administration. Mice whose righting reflex disappeared for at least 1 minute within 30 minutes were taken as falling asleep, the number of sleeping animals in each group was recorded, and the rate of falling asleep was calculated.MAIN OUTCOME MEASURES: Synergistic action of Yinao capsules with pentobarbital sodium of threshold and sub-threshold dosages in hypnosia and sedation.spontaneous activity of mice: The times of spontaneous activities within 10 minutes in the large and middle dosage of Yinao capsules groups and Kangnaoshuai capsules group [( 138.0 ± 37.0), (156.8 ± 28.3), (133.3 ±46.1) times] were obviously fewer than those in the control group [(204.3±61.3) times, P ＜ 0.05 -0.01].The arising times within 10 minutes in the middle and small dosages of Yinao capsules groups and Kangnaoshuai capsules group [(30.7 ± 18.3), (26.5 ± 11.2), (24.2± 11.6) times] were obviously fewer than pentobarbital sodium of threshold dosage: The sleeping latencies in the large and middle dosages of Yinao capsules groups and Kangnaoshuai capsules group [(4.49± 1.84), (4.83 ± 1.72), (3.85 ±1.94) minutes] were obviously shorter than that in the control group [(6.73 ±2.75) minutes, P ＜ 0.05 - 0.01]. The sleeping time in the large, middle and small dosages of Yinao capsules groups and Kangnaoshuai capsules group [(89.0±38.42), (67.21 ±24.07), (66.28 ± 18.94), (84.36 ± 29.81 ) minutes] were obviously longer than that in the capsules with pentobarbital sodium of sub-threshold dosage: The rates of falling asleep in thc large and middle dosages of Yinao capsules groups were higher than that in the control group [56% (9/16), 38% (6/16),6% (1/16), P ＜ 0.01, 0.05], whereas Kangnaoshuai capsules and small dosage of Yinao capsules had no synergistic action with pentobarbital sodium of sub-threshold dosage (P ＞ 0.05).CONCLUSION: Yinao capsules have synergistic action with pentobarbital sodium in hypnosia. Yinao capsules possess obvious sedative and hypnotic effects in a dosage-dependent manner.