[Coffee and caffeine. Various selected aspects for everyday practice].

Moderate consumption of methylxanthines, for example in coffee, tea, cola-drinks and other foodstuffs containing caffeine, is probably without particular health risks, insofar as other risk factors (smoking, alcohol, nutrition in general) can be kept under control. To avoid prohibition on one hand and to evaluate necessary restrictions concerning caffeine consumption individually on the other hand is an artful task in daily medical practice. Coffee is one of the chemically most complex consumables, and its physiologic effects are accordingly complex and to a great deal still unknown. Caffeine in moderate amounts has practically neither a negative effect on health nor does it promote pathogenesis of disease. Only excessive use may induce problems. Therefore, excessive use of caffeine is assumed in those persons, in which withdrawal is followed by withdrawal symptoms (41). Many aspects of caffeine and biomedical caffeine effects cannot yet be explained. Nevertheless, from the medical point of view, there are no objections to a moderate use of caffeine with one exception: if the coffee break is used as a pretext for smoking.