The goal of a new study published in The Dermatologist was to describe the frequency of contact sensitization to various preservatives used in cosmetics.This was a retrospective study that analyzed data from the Information Network of Departments of Dermatology (IVDK) for the years 2009-2018.The findings showed that the frequency of sensitization to methylisothiazolinone (MI) has increased from 2.0% in 2009 to 7.2% in 2013. Since 2014, the rate has been further declining. Increasing the patch test concentration of methyldibromo glutaronitrile (MDBGN) in 2016 has led to a sudden rise in positive patch test reactions from 2% to more than 4.5%. On the other hand, allergic reactions to other preservatives occurred in less than 1% of the patients tested.The decline in the sensitization to MI was attributed to the corresponding restrictions on its use since 2014. Owing to the lack of widespread exposure to MDBGN since 2008, the new, higher test concentration elicits many false-positive test reactions and explains the sudden rise in positive patch test reactions since 2016. Whereas, despite widespread use, phenoxyethanol, benzoates, benzyl alcohol, parabens and sorbates rarely cause allergic reactions. Thus, these can be recommended for use in cosmetics from the epidemiological-allergological point of view.