Lice have been present on our planet for millions of years. They are permanent ectoparasites of birds and mammals. Lice are divided into four sub-orders: the chewing louse suborders Amblycera, Ischnocera and Rhynchophthirin, and the sucking suborder Anoplura. The sucking suborder Anoplura contains about 500 species, of which three species are parasitic to humans; two species from the genus Pediculus: P. humanus humanus (body louse), P.humanus capitis (head louse) and one from the genus Pthirus or Phtirius: P.pubis (pubic louse). Head lice infestation is common in institutionsfor early childhood and preschool education and most commonly affects children aged 3 to 12, but can also affect people in close contact with them. Pediculosis affects everyone, regardles of their economic status and hygiene. Head lice are thin, small insects, longer than wider, that grow to a maximum of 3 mm. They have adapted to live on the scalp of humans exclusively. This is where head lice find a temperature of about 30°C and a humidity of around 90%, and lots of food, which overall gives them the optimal living conditions. They feed on blood, which they suck from the skin on the scalp and can survive up to 48 hours without food. Head lice do not transmit diseases. Head lice can be treated with repellents, or by chemical and mechanical suppression. There are new products on the market that do not contain insecticidal ingredients. Nits are firmly attached to the hair strand and need to be thoroughly combed with special lice combs every day for seven days. All children should be treated at the same time. Thorough cleaning of the institution or household is not required.