[Melatonin: a new wonder drug?].

Melatonin, the hormone of the pineal gland is secreted during the night. It provides temporal information on diurnal and seasonal variation to the brain and the body. It is not a "classical" sleeping pill, and it should not be taken as such. The sole sufficiently investigated indication in humans is the treatment of certain sleep disorders from the group of sleep-wake-rhythm disturbances. These manifest themselves by sleep time of the day, i.e. in shift workers, after flights across time zones and in some blind and aged persons. None of the other promises, i.e. that melatonin conserves youth, prolong life, heals cancer or is a free radicals scavenger, have been confirmed by clinical studies.