Sleeping disorders and restlessness are widely spread among the population. Conventional pharmaceuticals against such disturbances on a chemical basis, such as benzodiazepines and barbiturates show a strong potential of generating dependance and they also have a high rate of adverse reactions. Plant based pharmaceuticals may constitute an alternative that is more mild and well-tolerated in the case of insomnia. This thesis deals primarily with the sedative effects of three selective herbal medicinal plants that have already been applied against insomnia for centuries. By means of literature research medicinal plant profiles of valerian (valeriana officinalis), passion flower (passiflora incarnata) and lemon balm (melissa officinalis), were created. The basis for the research were mainly scientific publications. The aim of this piece of work was to give a comprehensive survey of the botany, the constituents, the history, the variety of use and the posolgy of these plants and to be able to make statements about the mechanisms of action, the efficacy and the safety based on the assessment of older, traditional and also latest scientific work and clinical studies.