The significance of this study stems from the fact that the previously therapeutic indications of Hyoscine to prevent nausea and vomiting may be related to its effect on the nervous system in general, and memory in particular, but the exact mechanism is unknown and requires additional investigations. To study the neurobehavioral effects of Hyoscine and their relationship to serotonin and acetylcholine in mice, the mice divided into 3 groups, each group consisting of 10 animals. The first group was a control, the second group was given a dose of 2 mg/kg, and the third group was given 4 mg/kg. Neurobehavioral experiments were conducted for half of the animals after two weeks of dosing, the rest of animals after 4 weeks. The measured LD50 of Hyoscine was 196 mg/kg when given by i.p. injection. A decrease in motor activity was recorded with doses of 2 and 4 mg/kg and an increase in the number of rearing times as compared to the control group after 2 and 4 weeks of treatment. The dose of 4 mg/kg of Hyoscine indicated a significant increase in serotonin levels compared to the control group. The Hyoscine groups of 2 and 4 mg/kg had significantly lower acetylcholine and COMT enzyme levels than the control group. Hyoscine affects the nervous system by increasing the levels of serotonin, acetylcholine and COMT enzyme in the blood of mice.