Background. Distress, due to pain, fear/anxiety, dyspnea, or delirium is common among critically ill patients. Distress may manifest clinically as agitation that is often associated with ventilator asynchrony and vital sign abnormalities. Regardless, distress needs to be treated to comfort the patient, ameliorate agitation that may interfere with supportive care, and attenuate increases in sympathetic tone, which may have untoward physiological effects. Purpose. Common sedative-analgesic medications used to treat distress in critically ill adults. Identifying the cause of distress and using this information to select the optimal sedative-analgesic agent is discussed separately. The aim of the study was to evaluate effectiveness of the new sedative drug complex “Flegmen” in preclinical study. Materials and Methods. The elemental composition of sedative assemblage "Flegmen" was analyzed by the method of mass spectrometry induction coupled plasma on the instrument ICP-MS 7500a AT the company "Agilent Technologies". Sedative assemblage "Flegmen" contains 39 elements. In the greatest number of macrocells in the sedative assemblage "Flegmen" contains chlorine, phosphorous, bromine, sodium, chromium, titanium, zinc and strontium. Also set the content of calcium (9.6 µg), which relieves the consequences of stress. Amino acid composition of sedative collection was studied analyzer. Identification of amino acids of the collection and their quantitative content in nanomolar was calculated according to the integrator, which is supplied with amino acid analyzer. Clinical studies were performed in the Republican Specialized Scientific-Practical Center (RSSPC) of Therapy and Medical Rehabilitation, the Department of Neurology, Departments of GP-therapy, Clinical Allergology, Propedeutics of Internal Diseases, Hematology, and Professional Diseases in the Tashkent Medical Academy. Experiments and Results. The study included 90 patients who received drug, which is studied, and 60 patients received the drug comparison on outpatient and inpatient care. Clinical study was divided three particular clinical trials. Patients were divided into two groups: basic and control. Mean age was 44.5±3.61 year. According to evaluation of the effectiveness of the drug "Flegmen" was found extremely tolerability in all 90 (100%) patients. Side effects were not revealed in the research. Conclusion. It was confirmed that sedative assemblage "Flegmen" is the most effective at treatment of patients with various diseases followed by an asteno-neurotic syndrome and neuroses that allows to recommend it for use in practical health care.