In order to obtain new, cluster-forming antibiotic compounds, teicoplanin pseudoaglycone derivatives containing two lipophilic n-octyl chains have been synthesized. The compounds proved to be poor antibacterials, but, surprisingly, they exhibited potent anti-influenza virus activity against influenza A strains. This antiviral action was related to inhibition of the binding interaction between the virus and the host cell. Related analogs bearing methyl substituents in lieu of the octyl chains, displayed no anti-influenza virus activity. Hence, an interaction between the active, dually n-octylated compounds and the lipid bilayer of the host cell can be postulated, to explain the observed inhibition of influenza virus attachment.