The present invention relates to novel neuraminidase activity inhibitors and use thereof for prophylaxis and treatment of influenza infection, that is, to fluorosubstituted 4-acetamido-5-guanidino-3-(pentan-3-yloxy)cyclohex-1-enecarboxylic acids, their esters of the general formula 1, pharmaceutically acceptable salts and/or hydrates thereof, wherein R represents hydrogen, optionally substituted C 1 -C 5 alkyl, C 2 -C 5 alkenyl or C 2 -C 5 alkynyl； Rf represents CH 2 F or CHF 2 . Pharmaceutical composition is given, method for its preparation, as well as method for prophylaxis and treatment of viral diseases.
