The drugs Valerinae radix, Crataegi fructus, Leonuri herba and Melissae folium were used to produce a liquid plant extract. The experiment revealed that the extraction with 70% ethanol achieved the highest concentration of extractable active principles. The optimal conditions for obtaining a sedative extract are established when the method of repercolation is used, and in the production itself the batch of the drug is divided into equally large doses and a pre-prepared mixture of plant drugs is extracted. The extract prepared by this manner remains stable for the whole period of storage, i.e., 24 months.