Melatonin is a natural hormone originating from the pineal gland. It has a circadian secretion pattern with highest concentrations during the night. Intense research during the past 20-30 years has revealed that when melatonin is given in supra-physiologic doses, i.e. as tablets in milligram doses, it has a number of very important effects. Thus, melatonin can be used for various sleep disorders including insomnia, and circadian disturbances such...