Abstract: The present invention relates to a condensation product obtainable by reaction of a1) at least one aromatic system or heteroaromatic system, a2) at least one carbonyl compound, a3) if appropriate at least one sulfonating agent, and a4) if appropriate at least one urea derivative, where the condensation product has a molecular weight Mw of at least 300 g/mol, for use in a method for the treatment of COVID-19. The invention further relates to a use of the condensation product in a therapeutic method for the treatment of COVID-19; to a use of the condensation product as disinfectant against the virus SARS-CoV-2; and to a use of the condensation product for the production of a medicament which is an antiviral agent against SARS-CoV-2.