[Domestic humidifiers. What do we know about them?].
Popular opinion assumes that environmental humidity relieves the clinical symptoms of respiratory tract diseases. Various types of home humidifiers are available on the market. Parents buy them in the belief that they will improve their children's well-being but are usually unaware of whether these devices provide a real benefit. Pediatricians should bear the main responsibility in the task of informing and guiding families in the use of home humidifiers but general lack of knowledge on the subject and the scarcity of published data make this task difficult. The aim of this review is to increase general knowledge of home humidifiers. We describe what they are, their main types, their basic functioning, advantages and disadvantages and the importance of suitable maintenance. We define what environmental humidity means, how it can change according to temperature and how it can influence human health. Finally, we suggest that optimal relative humidity is approximately 40-60 % and that it should be measured before using a home humidifier.