Resume. Relevance. The acute toxicity evaluation is the anecessary stage of preclinical research of the new original anxiolytic drug GML-1. The present investigation aim is study of the GML-1 acute toxicity. Methods. GML-1 was administered once orally and intraperitoneally to mice and rats in the maximum possible volumes for each of the administration methods and for each animal species, at the highest possible concentrations. Equivalent volume of 1 % starch solution was administered to animals of the control groups. Euthanasia and pathoanatomical dissection were performed 14 days after the drug administration. The animal intoxication periods with a detailed description of the observed clinical picture were registered. Results. The mean lethal doses were not identified because GML-1 did not cause death of animals at injection of the maximum allowable volumes and maximum allowable concentrations. The morphological view of the internal organs, detected during pathoanatomical dissection of all experimental animals, did not differ from that observed in control animals. Conclusion. It was determined that the drug GML-1 at oral and intraperitoneal injection concerns to low-toxic substances. According to classification Sidorov K.K. (1973) this drug may be related to 4th toxicity class.