Introduction. Among wild plants that have an effect on the nervous system, species of the genus Melampyrum L. are distinguished, in particular, Melampyrum sylvaticum L. Extracts from the aerial part of the plant have long been used in folk medicine as sedatives and anticonvulsants. Currently, a number of studies are being carried out to confirm the possibility of using wildflower and drugs based on it in scientific medicine, as well as to obtain a drug with low toxicity, complex sedative and anticonvulsant activity, which will expand the arsenal of drugs used to treat diseases of the nervous system.Aim. To investigate the in vivo acute toxicity, anticonvulsant and sedative activity of a dry alcohol extract from the aerial part of Melampyrum sylvaticum.Materials and methods. The extract was obtained by extracting substances from the aerial part of Melampyrum sylvaticum with 50 % ethanol, by the method of repercolation with an equal loading of raw materials, followed by evaporation to a dry residue. The study of pharmacological properties was carried out on nonlinear white mice of both sexes weighing 17–25 g. Acute toxicity of the extract was determined by oral administration in doses up to 5000 mg/kg. Anticonvulsant activity was evaluated in the corazole convulsion test, sedative activity was evaluated in the open field test.Results and discussion. When determining the acute toxicity of a dry alcoholic extract from the aerial part of Melampyrum sylvaticum, there was no lethality in the experimental group of animals. LD50 could not be determined. In the corazol convulsion test, it was shown that oral administration of the extract at a dose of 100 mg/kg does not affect the latent period of convulsions, but significantly increases the life expectancy of animals. At a dose of 200 mg/kg, the latent period of seizures and life expectancy significantly increased, and the survival rate of animals was 20 %. When studying sedative activity of the extract from Melampyrum sylvaticum in the open field test, a decrease in vertical activity, a decrease in the number of vertical stands, a decrease in horizontal activity along the periphery and the number of animals entering the center of the area were noted, which indicates a suppression of orienting-exploratory behavior. In the experiment, there was a decrease in the intensity of grooming as an indicator of anxiety for this group of animals. A course of administration of the extract for thirty days led to a decrease in the vertical activity of mice and inhibition of orienting-exploratory behavior.Conclusion. It was found that a dry alcoholic extract from the aerial part of Melampyrum sylvaticum exhibits biological activity in animal experiments, compensating for the effect of corazol, and has a pronounced anticonvulsant and sedative effect. The LD50 of the extract when administered orally was more than 5000 mg/kg.