The author recommends differentiated topical treatment of ichthyoses. At present, urea is the base curative for the five main types of this heterogenous group of diseases. Urea is not only effective as a keratolytic agent, but also in its ability to bind water. Whether the inhibition of proliferation, enhancement of penetration and the antimicrobial effects observed with urea are therapeutically important remains to be investigated. The combination of urea and tretinoin displays a beneficial effect on the clinical symptoms of nonerythematosus types of ichthyoses. The more severe the keratinization disorder, the sooner additional systemic treatment with retinoids is indicated.